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      1 // Copyright (c) 2013 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 "content/browser/renderer_host/media/web_contents_tracker.h"
      6 
      7 #include "base/message_loop/message_loop_proxy.h"
      8 #include "content/public/browser/browser_thread.h"
      9 #include "content/public/browser/render_process_host.h"
     10 #include "content/public/browser/render_view_host.h"
     11 #include "content/public/browser/web_contents.h"
     12 
     13 namespace content {
     14 
     15 WebContentsTracker::WebContentsTracker() {}
     16 
     17 WebContentsTracker::~WebContentsTracker() {
     18   DCHECK(!web_contents()) << "BUG: Still observering!";
     19 }
     20 
     21 void WebContentsTracker::Start(int render_process_id, int render_view_id,
     22                                const ChangeCallback& callback) {
     23   DCHECK(!message_loop_.get() || message_loop_->BelongsToCurrentThread());
     24 
     25   message_loop_ = base::MessageLoopProxy::current();
     26   DCHECK(message_loop_.get());
     27   callback_ = callback;
     28 
     29   BrowserThread::PostTask(
     30       BrowserThread::UI, FROM_HERE,
     31       base::Bind(&WebContentsTracker::LookUpAndObserveWebContents, this,
     32                  render_process_id, render_view_id));
     33 }
     34 
     35 void WebContentsTracker::Stop() {
     36   DCHECK(message_loop_->BelongsToCurrentThread());
     37 
     38   callback_.Reset();
     39 
     40   BrowserThread::PostTask(
     41       BrowserThread::UI, FROM_HERE,
     42       base::Bind(&WebContentsTracker::Observe, this,
     43                  static_cast<WebContents*>(NULL)));
     44 }
     45 
     46 void WebContentsTracker::OnWebContentsChangeEvent() {
     47   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     48 
     49   WebContents* const wc = web_contents();
     50   RenderViewHost* const rvh = wc ? wc->GetRenderViewHost() : NULL;
     51   RenderProcessHost* const rph = rvh ? rvh->GetProcess() : NULL;
     52 
     53   const int render_process_id = rph ? rph->GetID() : MSG_ROUTING_NONE;
     54   const int render_view_id = rvh ? rvh->GetRoutingID() : MSG_ROUTING_NONE;
     55 
     56   message_loop_->PostTask(FROM_HERE,
     57       base::Bind(&WebContentsTracker::MaybeDoCallback, this,
     58                  render_process_id, render_view_id));
     59 }
     60 
     61 void WebContentsTracker::MaybeDoCallback(int render_process_id,
     62                                          int render_view_id) {
     63   DCHECK(message_loop_->BelongsToCurrentThread());
     64 
     65   if (!callback_.is_null())
     66     callback_.Run(render_process_id, render_view_id);
     67 }
     68 
     69 void WebContentsTracker::LookUpAndObserveWebContents(int render_process_id,
     70                                                      int render_view_id) {
     71   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
     72 
     73   RenderViewHost* const rvh =
     74       RenderViewHost::FromID(render_process_id, render_view_id);
     75   DVLOG_IF(1, !rvh) << "RenderViewHost::FromID("
     76                     << render_process_id << ", " << render_view_id
     77                     << ") returned NULL.";
     78   Observe(rvh ? WebContents::FromRenderViewHost(rvh) : NULL);
     79   DVLOG_IF(1, !web_contents())
     80       << "WebContents::FromRenderViewHost(" << rvh << ") returned NULL.";
     81 
     82   OnWebContentsChangeEvent();
     83 }
     84 
     85 void WebContentsTracker::RenderViewReady() {
     86   OnWebContentsChangeEvent();
     87 }
     88 
     89 void WebContentsTracker::AboutToNavigateRenderView(RenderViewHost* rvh) {
     90   OnWebContentsChangeEvent();
     91 }
     92 
     93 void WebContentsTracker::DidNavigateMainFrame(
     94     const LoadCommittedDetails& details, const FrameNavigateParams& params) {
     95   OnWebContentsChangeEvent();
     96 }
     97 
     98 void WebContentsTracker::WebContentsDestroyed(WebContents* web_contents) {
     99   OnWebContentsChangeEvent();
    100 }
    101 
    102 }  // namespace content
    103