Home | History | Annotate | Download | only in metrics 
      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include <math.h>
      6 
      7 #include "base/basictypes.h"
      8 #include "base/bind.h"
      9 #include "base/logging.h"
     10 #include "base/memory/scoped_ptr.h"
     11 #include "base/message_loop/message_loop.h"
     12 #include "base/message_loop/message_loop_proxy.h"
     13 #include "base/strings/string_number_conversions.h"
     14 #include "base/strings/string_split.h"
     15 #include "base/strings/string_tokenizer.h"
     16 #include "base/synchronization/condition_variable.h"
     17 #include "base/synchronization/lock.h"
     18 #include "base/threading/platform_thread.h"
     19 #include "base/time/time.h"
     20 #include "build/build_config.h"
     21 #include "chrome/browser/metrics/thread_watcher.h"
     22 #include "chrome/common/chrome_switches.h"
     23 #include "content/public/test/test_browser_thread.h"
     24 #include "testing/gtest/include/gtest/gtest.h"
     25 #include "testing/platform_test.h"
     26 
     27 using base::TimeDelta;
     28 using base::TimeTicks;
     29 using content::BrowserThread;
     30 
     31 enum State {
     32   INITIALIZED,        // Created ThreadWatch object.
     33   ACTIVATED,          // Thread watching activated.
     34   SENT_PING,          // Sent ping message to watched thread.
     35   RECEIVED_PONG,      // Received Pong message.
     36   DEACTIVATED,        // Thread watching de-activated.
     37 };
     38 
     39 enum WaitState {
     40   UNINITIALIZED,
     41   STARTED_WAITING,    // Start waiting for state_ to change to expected_state.
     42   STOPPED_WAITING,    // Done with the waiting.
     43   ALL_DONE,           // Done with waiting for STOPPED_WAITING.
     44 };
     45 
     46 enum CheckResponseState {
     47   UNKNOWN,
     48   SUCCESSFUL,         // CheckResponse was successful.
     49   FAILED,             // CheckResponse has failed.
     50 };
     51 
     52 // This class helps to track and manipulate thread state during tests. This
     53 // class also has utility method to simulate hanging of watched thread by making
     54 // the watched thread wait for a very long time by posting a task on watched
     55 // thread that keeps it busy. It also has an utility method to block running of
     56 // tests until ThreadWatcher object's post-condition state changes to an
     57 // expected state.
     58 class CustomThreadWatcher : public ThreadWatcher {
     59  public:
     60   base::Lock custom_lock_;
     61   base::ConditionVariable state_changed_;
     62   State thread_watcher_state_;
     63   WaitState wait_state_;
     64   CheckResponseState check_response_state_;
     65   uint64 ping_sent_;
     66   uint64 pong_received_;
     67   uint64 success_response_;
     68   uint64 failed_response_;
     69   base::TimeTicks saved_ping_time_;
     70   uint64 saved_ping_sequence_number_;
     71 
     72   CustomThreadWatcher(const BrowserThread::ID thread_id,
     73                       const std::string thread_name,
     74                       const TimeDelta& sleep_time,
     75                       const TimeDelta& unresponsive_time)
     76       : ThreadWatcher(WatchingParams(thread_id, thread_name, sleep_time,
     77                       unresponsive_time, ThreadWatcherList::kUnresponsiveCount,
     78                       true, ThreadWatcherList::kLiveThreadsThreshold)),
     79         state_changed_(&custom_lock_),
     80         thread_watcher_state_(INITIALIZED),
     81         wait_state_(UNINITIALIZED),
     82         check_response_state_(UNKNOWN),
     83         ping_sent_(0),
     84         pong_received_(0),
     85         success_response_(0),
     86         failed_response_(0),
     87         saved_ping_time_(base::TimeTicks::Now()),
     88         saved_ping_sequence_number_(0) {
     89   }
     90 
     91   State UpdateState(State new_state) {
     92     State old_state;
     93     {
     94       base::AutoLock auto_lock(custom_lock_);
     95       old_state = thread_watcher_state_;
     96       if (old_state != DEACTIVATED)
     97         thread_watcher_state_ = new_state;
     98       if (new_state == SENT_PING)
     99         ++ping_sent_;
    100       if (new_state == RECEIVED_PONG)
    101         ++pong_received_;
    102       saved_ping_time_ = ping_time();
    103       saved_ping_sequence_number_ = ping_sequence_number();
    104     }
    105     state_changed_.Broadcast();
    106     return old_state;
    107   }
    108 
    109   WaitState UpdateWaitState(WaitState new_state) {
    110     WaitState old_state;
    111     {
    112       base::AutoLock auto_lock(custom_lock_);
    113       old_state = wait_state_;
    114       wait_state_ = new_state;
    115     }
    116     state_changed_.Broadcast();
    117     return old_state;
    118   }
    119 
    120   virtual void ActivateThreadWatching() OVERRIDE {
    121     State old_state = UpdateState(ACTIVATED);
    122     EXPECT_EQ(old_state, INITIALIZED);
    123     ThreadWatcher::ActivateThreadWatching();
    124   }
    125 
    126   virtual void DeActivateThreadWatching() OVERRIDE {
    127     State old_state = UpdateState(DEACTIVATED);
    128     EXPECT_TRUE(old_state == ACTIVATED || old_state == SENT_PING ||
    129                 old_state == RECEIVED_PONG);
    130     ThreadWatcher::DeActivateThreadWatching();
    131   }
    132 
    133   virtual void PostPingMessage() OVERRIDE {
    134     State old_state = UpdateState(SENT_PING);
    135     EXPECT_TRUE(old_state == ACTIVATED || old_state == RECEIVED_PONG);
    136     ThreadWatcher::PostPingMessage();
    137   }
    138 
    139   virtual void OnPongMessage(uint64 ping_sequence_number) OVERRIDE {
    140     State old_state = UpdateState(RECEIVED_PONG);
    141     EXPECT_TRUE(old_state == SENT_PING || old_state == DEACTIVATED);
    142     ThreadWatcher::OnPongMessage(ping_sequence_number);
    143   }
    144 
    145   virtual void OnCheckResponsiveness(uint64 ping_sequence_number) OVERRIDE {
    146     ThreadWatcher::OnCheckResponsiveness(ping_sequence_number);
    147     {
    148       base::AutoLock auto_lock(custom_lock_);
    149       if (responsive_) {
    150         ++success_response_;
    151         check_response_state_ = SUCCESSFUL;
    152       } else {
    153         ++failed_response_;
    154         check_response_state_ = FAILED;
    155       }
    156     }
    157     // Broadcast to indicate we have checked responsiveness of the thread that
    158     // is watched.
    159     state_changed_.Broadcast();
    160   }
    161 
    162   void WaitForWaitStateChange(TimeDelta wait_time, WaitState expected_state) {
    163     DCHECK(!WatchDogThread::CurrentlyOnWatchDogThread());
    164     TimeTicks end_time = TimeTicks::Now() + wait_time;
    165     {
    166       base::AutoLock auto_lock(custom_lock_);
    167       while (wait_state_ != expected_state && TimeTicks::Now() < end_time)
    168         state_changed_.TimedWait(end_time - TimeTicks::Now());
    169     }
    170   }
    171 
    172   void VeryLongMethod(TimeDelta wait_time) {
    173     DCHECK(!WatchDogThread::CurrentlyOnWatchDogThread());
    174     WaitForWaitStateChange(wait_time, STOPPED_WAITING);
    175     UpdateWaitState(ALL_DONE);
    176   }
    177 
    178   State WaitForStateChange(const TimeDelta& wait_time, State expected_state) {
    179     DCHECK(!WatchDogThread::CurrentlyOnWatchDogThread());
    180     UpdateWaitState(STARTED_WAITING);
    181 
    182     State exit_state = INITIALIZED;
    183     // Keep the thread that is running the tests waiting until ThreadWatcher
    184     // object's state changes to the expected_state or until wait_time elapses.
    185     for (uint32 i = 0; i < unresponsive_threshold_; ++i) {
    186         TimeTicks end_time = TimeTicks::Now() + wait_time;
    187         {
    188           base::AutoLock auto_lock(custom_lock_);
    189           while (thread_watcher_state_ != expected_state &&
    190                  TimeTicks::Now() < end_time) {
    191             TimeDelta state_change_wait_time = end_time - TimeTicks::Now();
    192             state_changed_.TimedWait(state_change_wait_time);
    193           }
    194           // Capture the thread_watcher_state_ before it changes and return it
    195           // to the caller.
    196           exit_state = thread_watcher_state_;
    197           if (exit_state == expected_state)
    198             break;
    199         }
    200     }
    201     UpdateWaitState(STOPPED_WAITING);
    202     return exit_state;
    203   }
    204 
    205   CheckResponseState WaitForCheckResponse(const TimeDelta& wait_time,
    206                                           CheckResponseState expected_state) {
    207     DCHECK(!WatchDogThread::CurrentlyOnWatchDogThread());
    208     UpdateWaitState(STARTED_WAITING);
    209 
    210     CheckResponseState exit_state = UNKNOWN;
    211     // Keep the thread that is running the tests waiting until ThreadWatcher
    212     // object's check_response_state_ changes to the expected_state or until
    213     // wait_time elapses.
    214     for (uint32 i = 0; i < unresponsive_threshold_; ++i) {
    215         TimeTicks end_time = TimeTicks::Now() + wait_time;
    216         {
    217           base::AutoLock auto_lock(custom_lock_);
    218           while (check_response_state_ != expected_state &&
    219                  TimeTicks::Now() < end_time) {
    220             TimeDelta state_change_wait_time = end_time - TimeTicks::Now();
    221             state_changed_.TimedWait(state_change_wait_time);
    222           }
    223           // Capture the check_response_state_ before it changes and return it
    224           // to the caller.
    225           exit_state = check_response_state_;
    226           if (exit_state == expected_state)
    227             break;
    228         }
    229     }
    230     UpdateWaitState(STOPPED_WAITING);
    231     return exit_state;
    232   }
    233 };
    234 
    235 class ThreadWatcherTest : public ::testing::Test {
    236  public:
    237   static const TimeDelta kSleepTime;
    238   static const TimeDelta kUnresponsiveTime;
    239   static const BrowserThread::ID io_thread_id;
    240   static const std::string io_thread_name;
    241   static const BrowserThread::ID db_thread_id;
    242   static const std::string db_thread_name;
    243   static const std::string crash_on_hang_seconds;
    244   static const std::string crash_on_hang_thread_names;
    245   static const std::string thread_names_and_live_threshold;
    246   static const std::string crash_on_hang_thread_data;
    247   CustomThreadWatcher* io_watcher_;
    248   CustomThreadWatcher* db_watcher_;
    249   ThreadWatcherList* thread_watcher_list_;
    250 
    251   ThreadWatcherTest()
    252       : setup_complete_(&lock_),
    253         initialized_(false) {
    254     db_thread_.reset(new content::TestBrowserThread(BrowserThread::DB));
    255     io_thread_.reset(new content::TestBrowserThread(BrowserThread::IO));
    256     watchdog_thread_.reset(new WatchDogThread());
    257     db_thread_->Start();
    258     io_thread_->Start();
    259     watchdog_thread_->Start();
    260 
    261     WatchDogThread::PostTask(
    262         FROM_HERE,
    263         base::Bind(&ThreadWatcherTest::SetUpObjects, base::Unretained(this)));
    264 
    265     WaitForSetUp(TimeDelta::FromMinutes(1));
    266   }
    267 
    268   void SetUpObjects() {
    269     DCHECK(WatchDogThread::CurrentlyOnWatchDogThread());
    270 
    271     // Setup the registry for thread watchers.
    272     thread_watcher_list_ = new ThreadWatcherList();
    273 
    274     // Create thread watcher object for the IO thread.
    275     io_watcher_ = new CustomThreadWatcher(io_thread_id, io_thread_name,
    276                                           kSleepTime, kUnresponsiveTime);
    277     EXPECT_EQ(io_watcher_, thread_watcher_list_->Find(io_thread_id));
    278 
    279     // Create thread watcher object for the DB thread.
    280     db_watcher_ = new CustomThreadWatcher(
    281         db_thread_id, db_thread_name, kSleepTime, kUnresponsiveTime);
    282     EXPECT_EQ(db_watcher_, thread_watcher_list_->Find(db_thread_id));
    283 
    284     {
    285       base::AutoLock lock(lock_);
    286       initialized_ = true;
    287     }
    288     setup_complete_.Signal();
    289   }
    290 
    291   void WaitForSetUp(TimeDelta wait_time) {
    292     DCHECK(!WatchDogThread::CurrentlyOnWatchDogThread());
    293     TimeTicks end_time = TimeTicks::Now() + wait_time;
    294     {
    295       base::AutoLock auto_lock(lock_);
    296       while (!initialized_ && TimeTicks::Now() < end_time)
    297         setup_complete_.TimedWait(end_time - TimeTicks::Now());
    298     }
    299   }
    300 
    301   virtual ~ThreadWatcherTest() {
    302     ThreadWatcherList::DeleteAll();
    303     io_watcher_ = NULL;
    304     db_watcher_ = NULL;
    305     io_thread_.reset();
    306     db_thread_.reset();
    307     watchdog_thread_.reset();
    308     thread_watcher_list_ = NULL;
    309   }
    310 
    311  private:
    312   base::Lock lock_;
    313   base::ConditionVariable setup_complete_;
    314   bool initialized_;
    315   scoped_ptr<content::TestBrowserThread> db_thread_;
    316   scoped_ptr<content::TestBrowserThread> io_thread_;
    317   scoped_ptr<WatchDogThread> watchdog_thread_;
    318 };
    319 
    320 // Define static constants.
    321 const TimeDelta ThreadWatcherTest::kSleepTime =
    322     TimeDelta::FromMilliseconds(50);
    323 const TimeDelta ThreadWatcherTest::kUnresponsiveTime =
    324     TimeDelta::FromMilliseconds(500);
    325 const BrowserThread::ID ThreadWatcherTest::io_thread_id = BrowserThread::IO;
    326 const std::string ThreadWatcherTest::io_thread_name = "IO";
    327 const BrowserThread::ID ThreadWatcherTest::db_thread_id = BrowserThread::DB;
    328 const std::string ThreadWatcherTest::db_thread_name = "DB";
    329 const std::string ThreadWatcherTest::crash_on_hang_thread_names = "UI,IO";
    330 const std::string ThreadWatcherTest::thread_names_and_live_threshold =
    331     "UI:4,IO:4";
    332 const std::string ThreadWatcherTest::crash_on_hang_thread_data =
    333     "UI:5:12,IO:5:12,FILE:5:12";
    334 
    335 TEST_F(ThreadWatcherTest, ThreadNamesOnlyArgs) {
    336   // Setup command_line arguments.
    337   CommandLine command_line(CommandLine::NO_PROGRAM);
    338   command_line.AppendSwitchASCII(switches::kCrashOnHangThreads,
    339                                  crash_on_hang_thread_names);
    340 
    341   // Parse command_line arguments.
    342   ThreadWatcherList::CrashOnHangThreadMap crash_on_hang_threads;
    343   uint32 unresponsive_threshold;
    344   ThreadWatcherList::ParseCommandLine(command_line,
    345                                       &unresponsive_threshold,
    346                                       &crash_on_hang_threads);
    347 
    348   // Verify the data.
    349   base::StringTokenizer tokens(crash_on_hang_thread_names, ",");
    350   std::vector<std::string> values;
    351   while (tokens.GetNext()) {
    352     const std::string& token = tokens.token();
    353     base::SplitString(token, ':', &values);
    354     std::string thread_name = values[0];
    355 
    356     ThreadWatcherList::CrashOnHangThreadMap::iterator it =
    357         crash_on_hang_threads.find(thread_name);
    358     bool crash_on_hang = (it != crash_on_hang_threads.end());
    359     EXPECT_TRUE(crash_on_hang);
    360     EXPECT_LT(0u, it->second.live_threads_threshold);
    361     EXPECT_LT(0u, it->second.unresponsive_threshold);
    362   }
    363 }
    364 
    365 TEST_F(ThreadWatcherTest, ThreadNamesAndLiveThresholdArgs) {
    366   // Setup command_line arguments.
    367   CommandLine command_line(CommandLine::NO_PROGRAM);
    368   command_line.AppendSwitchASCII(switches::kCrashOnHangThreads,
    369                                  thread_names_and_live_threshold);
    370 
    371   // Parse command_line arguments.
    372   ThreadWatcherList::CrashOnHangThreadMap crash_on_hang_threads;
    373   uint32 unresponsive_threshold;
    374   ThreadWatcherList::ParseCommandLine(command_line,
    375                                       &unresponsive_threshold,
    376                                       &crash_on_hang_threads);
    377 
    378   // Verify the data.
    379   base::StringTokenizer tokens(thread_names_and_live_threshold, ",");
    380   std::vector<std::string> values;
    381   while (tokens.GetNext()) {
    382     const std::string& token = tokens.token();
    383     base::SplitString(token, ':', &values);
    384     std::string thread_name = values[0];
    385 
    386     ThreadWatcherList::CrashOnHangThreadMap::iterator it =
    387         crash_on_hang_threads.find(thread_name);
    388     bool crash_on_hang = (it != crash_on_hang_threads.end());
    389     EXPECT_TRUE(crash_on_hang);
    390     EXPECT_EQ(4u, it->second.live_threads_threshold);
    391     EXPECT_LT(0u, it->second.unresponsive_threshold);
    392   }
    393 }
    394 
    395 TEST_F(ThreadWatcherTest, CrashOnHangThreadsAllArgs) {
    396   // Setup command_line arguments.
    397   CommandLine command_line(CommandLine::NO_PROGRAM);
    398   command_line.AppendSwitchASCII(switches::kCrashOnHangThreads,
    399                                  crash_on_hang_thread_data);
    400 
    401   // Parse command_line arguments.
    402   ThreadWatcherList::CrashOnHangThreadMap crash_on_hang_threads;
    403   uint32 unresponsive_threshold;
    404   ThreadWatcherList::ParseCommandLine(command_line,
    405                                       &unresponsive_threshold,
    406                                       &crash_on_hang_threads);
    407 
    408   // Verify the data.
    409   base::StringTokenizer tokens(crash_on_hang_thread_data, ",");
    410   std::vector<std::string> values;
    411   while (tokens.GetNext()) {
    412     const std::string& token = tokens.token();
    413     base::SplitString(token, ':', &values);
    414     std::string thread_name = values[0];
    415 
    416     ThreadWatcherList::CrashOnHangThreadMap::iterator it =
    417         crash_on_hang_threads.find(thread_name);
    418 
    419     bool crash_on_hang = (it != crash_on_hang_threads.end());
    420     EXPECT_TRUE(crash_on_hang);
    421 
    422     uint32 crash_live_threads_threshold = it->second.live_threads_threshold;
    423     EXPECT_EQ(5u, crash_live_threads_threshold);
    424 
    425     uint32 crash_unresponsive_threshold = it->second.unresponsive_threshold;
    426     uint32 crash_on_unresponsive_seconds =
    427         ThreadWatcherList::kUnresponsiveSeconds * crash_unresponsive_threshold;
    428     EXPECT_EQ(12u, crash_on_unresponsive_seconds);
    429   }
    430 }
    431 
    432 // Test registration. When thread_watcher_list_ goes out of scope after
    433 // TearDown, all thread watcher objects will be deleted.
    434 TEST_F(ThreadWatcherTest, Registration) {
    435   // Check ThreadWatcher object has all correct parameters.
    436   EXPECT_EQ(io_thread_id, io_watcher_->thread_id());
    437   EXPECT_EQ(io_thread_name, io_watcher_->thread_name());
    438   EXPECT_EQ(kSleepTime, io_watcher_->sleep_time());
    439   EXPECT_EQ(kUnresponsiveTime, io_watcher_->unresponsive_time());
    440   EXPECT_FALSE(io_watcher_->active());
    441 
    442   // Check ThreadWatcher object of watched DB thread has correct data.
    443   EXPECT_EQ(db_thread_id, db_watcher_->thread_id());
    444   EXPECT_EQ(db_thread_name, db_watcher_->thread_name());
    445   EXPECT_EQ(kSleepTime, db_watcher_->sleep_time());
    446   EXPECT_EQ(kUnresponsiveTime, db_watcher_->unresponsive_time());
    447   EXPECT_FALSE(db_watcher_->active());
    448 }
    449 
    450 // Test ActivateThreadWatching and DeActivateThreadWatching of IO thread. This
    451 // method also checks that pong message was sent by the watched thread and pong
    452 // message was received by the WatchDogThread. It also checks that
    453 // OnCheckResponsiveness has verified the ping-pong mechanism and the watched
    454 // thread is not hung.
    455 TEST_F(ThreadWatcherTest, ThreadResponding) {
    456   TimeTicks time_before_ping = TimeTicks::Now();
    457   // Activate watching IO thread.
    458   WatchDogThread::PostTask(
    459       FROM_HERE,
    460       base::Bind(&ThreadWatcher::ActivateThreadWatching,
    461                  base::Unretained(io_watcher_)));
    462 
    463   // Activate would have started ping/pong messaging. Expect atleast one
    464   // ping/pong messaging sequence to happen.
    465   io_watcher_->WaitForStateChange(kSleepTime + TimeDelta::FromMinutes(1),
    466                                   RECEIVED_PONG);
    467   EXPECT_GT(io_watcher_->ping_sent_, static_cast<uint64>(0));
    468   EXPECT_GT(io_watcher_->pong_received_, static_cast<uint64>(0));
    469   EXPECT_TRUE(io_watcher_->active());
    470   EXPECT_GE(io_watcher_->saved_ping_time_, time_before_ping);
    471   EXPECT_GE(io_watcher_->saved_ping_sequence_number_, static_cast<uint64>(0));
    472 
    473   // Verify watched thread is responding with ping/pong messaging.
    474   io_watcher_->WaitForCheckResponse(
    475       kUnresponsiveTime + TimeDelta::FromMinutes(1), SUCCESSFUL);
    476   EXPECT_GT(io_watcher_->success_response_, static_cast<uint64>(0));
    477   EXPECT_EQ(io_watcher_->failed_response_, static_cast<uint64>(0));
    478 
    479   // DeActivate thread watching for shutdown.
    480   WatchDogThread::PostTask(
    481       FROM_HERE,
    482       base::Bind(&ThreadWatcher::DeActivateThreadWatching,
    483       base::Unretained(io_watcher_)));
    484 }
    485 
    486 // This test posts a task on watched thread that takes very long time (this is
    487 // to simulate hanging of watched thread). It then checks for
    488 // OnCheckResponsiveness raising an alert (OnCheckResponsiveness returns false
    489 // if the watched thread is not responding).
    490 TEST_F(ThreadWatcherTest, ThreadNotResponding) {
    491   // Simulate hanging of watched thread by making the watched thread wait for a
    492   // very long time by posting a task on watched thread that keeps it busy.
    493   // It is safe to use base::Unretained because test is waiting for the method
    494   // to finish.
    495   BrowserThread::PostTask(
    496       io_thread_id,
    497       FROM_HERE,
    498       base::Bind(&CustomThreadWatcher::VeryLongMethod,
    499                  base::Unretained(io_watcher_),
    500                  kUnresponsiveTime * 10));
    501 
    502   // Activate thread watching.
    503   WatchDogThread::PostTask(
    504       FROM_HERE,
    505       base::Bind(&ThreadWatcher::ActivateThreadWatching,
    506                  base::Unretained(io_watcher_)));
    507 
    508   // Verify watched thread is not responding for ping messages.
    509   io_watcher_->WaitForCheckResponse(
    510       kUnresponsiveTime + TimeDelta::FromMinutes(1), FAILED);
    511   EXPECT_EQ(io_watcher_->success_response_, static_cast<uint64>(0));
    512   EXPECT_GT(io_watcher_->failed_response_, static_cast<uint64>(0));
    513 
    514   // DeActivate thread watching for shutdown.
    515   WatchDogThread::PostTask(
    516       FROM_HERE,
    517       base::Bind(&ThreadWatcher::DeActivateThreadWatching,
    518                  base::Unretained(io_watcher_)));
    519 
    520   // Wait for the io_watcher_'s VeryLongMethod to finish.
    521   io_watcher_->WaitForWaitStateChange(kUnresponsiveTime * 10, ALL_DONE);
    522 }
    523 
    524 // Test watching of multiple threads with all threads not responding.
    525 TEST_F(ThreadWatcherTest, MultipleThreadsResponding) {
    526   // Check for DB thread to perform ping/pong messaging.
    527   WatchDogThread::PostTask(
    528       FROM_HERE,
    529       base::Bind(&ThreadWatcher::ActivateThreadWatching,
    530                  base::Unretained(db_watcher_)));
    531 
    532   // Check for IO thread to perform ping/pong messaging.
    533   WatchDogThread::PostTask(
    534       FROM_HERE,
    535       base::Bind(&ThreadWatcher::ActivateThreadWatching,
    536                  base::Unretained(io_watcher_)));
    537 
    538   // Verify DB thread is responding with ping/pong messaging.
    539   db_watcher_->WaitForCheckResponse(
    540       kUnresponsiveTime + TimeDelta::FromMinutes(1), SUCCESSFUL);
    541   EXPECT_GT(db_watcher_->ping_sent_, static_cast<uint64>(0));
    542   EXPECT_GT(db_watcher_->pong_received_, static_cast<uint64>(0));
    543   EXPECT_GE(db_watcher_->ping_sequence_number_, static_cast<uint64>(0));
    544   EXPECT_GT(db_watcher_->success_response_, static_cast<uint64>(0));
    545   EXPECT_EQ(db_watcher_->failed_response_, static_cast<uint64>(0));
    546 
    547   // Verify IO thread is responding with ping/pong messaging.
    548   io_watcher_->WaitForCheckResponse(
    549       kUnresponsiveTime + TimeDelta::FromMinutes(1), SUCCESSFUL);
    550   EXPECT_GT(io_watcher_->ping_sent_, static_cast<uint64>(0));
    551   EXPECT_GT(io_watcher_->pong_received_, static_cast<uint64>(0));
    552   EXPECT_GE(io_watcher_->ping_sequence_number_, static_cast<uint64>(0));
    553   EXPECT_GT(io_watcher_->success_response_, static_cast<uint64>(0));
    554   EXPECT_EQ(io_watcher_->failed_response_, static_cast<uint64>(0));
    555 
    556   // DeActivate thread watching for shutdown.
    557   WatchDogThread::PostTask(
    558       FROM_HERE,
    559       base::Bind(&ThreadWatcher::DeActivateThreadWatching,
    560                  base::Unretained(io_watcher_)));
    561 
    562   WatchDogThread::PostTask(
    563       FROM_HERE,
    564       base::Bind(&ThreadWatcher::DeActivateThreadWatching,
    565                  base::Unretained(db_watcher_)));
    566 }
    567 
    568 // Test watching of multiple threads with one of the threads not responding.
    569 TEST_F(ThreadWatcherTest, MultipleThreadsNotResponding) {
    570   // Simulate hanging of watched thread by making the watched thread wait for a
    571   // very long time by posting a task on watched thread that keeps it busy.
    572   // It is safe ot use base::Unretained because test is waiting for the method
    573   // to finish.
    574   BrowserThread::PostTask(
    575       io_thread_id,
    576       FROM_HERE,
    577       base::Bind(&CustomThreadWatcher::VeryLongMethod,
    578                  base::Unretained(io_watcher_),
    579                  kUnresponsiveTime * 10));
    580 
    581   // Activate watching of DB thread.
    582   WatchDogThread::PostTask(
    583       FROM_HERE,
    584       base::Bind(&ThreadWatcher::ActivateThreadWatching,
    585                  base::Unretained(db_watcher_)));
    586 
    587   // Activate watching of IO thread.
    588   WatchDogThread::PostTask(
    589       FROM_HERE,
    590       base::Bind(&ThreadWatcher::ActivateThreadWatching,
    591                  base::Unretained(io_watcher_)));
    592 
    593   // Verify DB thread is responding with ping/pong messaging.
    594   db_watcher_->WaitForCheckResponse(
    595       kUnresponsiveTime + TimeDelta::FromMinutes(1), SUCCESSFUL);
    596   EXPECT_GT(db_watcher_->success_response_, static_cast<uint64>(0));
    597   EXPECT_EQ(db_watcher_->failed_response_, static_cast<uint64>(0));
    598 
    599   // Verify IO thread is not responding for ping messages.
    600   io_watcher_->WaitForCheckResponse(
    601       kUnresponsiveTime + TimeDelta::FromMinutes(1), FAILED);
    602   EXPECT_EQ(io_watcher_->success_response_, static_cast<uint64>(0));
    603   EXPECT_GT(io_watcher_->failed_response_, static_cast<uint64>(0));
    604 
    605   // DeActivate thread watching for shutdown.
    606   WatchDogThread::PostTask(
    607       FROM_HERE,
    608       base::Bind(&ThreadWatcher::DeActivateThreadWatching,
    609                  base::Unretained(io_watcher_)));
    610   WatchDogThread::PostTask(
    611       FROM_HERE,
    612       base::Bind(&ThreadWatcher::DeActivateThreadWatching,
    613                  base::Unretained(db_watcher_)));
    614 
    615   // Wait for the io_watcher_'s VeryLongMethod to finish.
    616   io_watcher_->WaitForWaitStateChange(kUnresponsiveTime * 10, ALL_DONE);
    617 }
    618