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      1 // Copyright 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 "cc/output/begin_frame_args.h"
      6 #include "ui/gfx/frame_time.h"
      7 
      8 namespace cc {
      9 
     10 BeginFrameArgs::BeginFrameArgs()
     11   : frame_time(base::TimeTicks()),
     12     deadline(base::TimeTicks()),
     13     interval(base::TimeDelta::FromMicroseconds(-1)) {
     14 }
     15 
     16 BeginFrameArgs::BeginFrameArgs(base::TimeTicks frame_time,
     17                                base::TimeTicks deadline,
     18                                base::TimeDelta interval)
     19   : frame_time(frame_time),
     20     deadline(deadline),
     21     interval(interval)
     22 {}
     23 
     24 BeginFrameArgs BeginFrameArgs::Create(base::TimeTicks frame_time,
     25                                       base::TimeTicks deadline,
     26                                       base::TimeDelta interval) {
     27   return BeginFrameArgs(frame_time, deadline, interval);
     28 }
     29 
     30 BeginFrameArgs BeginFrameArgs::CreateForSynchronousCompositor() {
     31   // For WebView/SynchronousCompositor, we always want to draw immediately,
     32   // so we set the deadline to 0 and guess that the interval is 16 milliseconds.
     33   return BeginFrameArgs(gfx::FrameTime::Now(),
     34                         base::TimeTicks(),
     35                         DefaultInterval());
     36 }
     37 
     38 BeginFrameArgs BeginFrameArgs::CreateForTesting() {
     39   base::TimeTicks now = gfx::FrameTime::Now();
     40   return BeginFrameArgs(now,
     41                         now + (DefaultInterval() / 2),
     42                         DefaultInterval());
     43 }
     44 
     45 BeginFrameArgs BeginFrameArgs::CreateExpiredForTesting() {
     46   base::TimeTicks now = gfx::FrameTime::Now();
     47   return BeginFrameArgs(now,
     48                         now - DefaultInterval(),
     49                         DefaultInterval());
     50 }
     51 
     52 // This is a hard-coded deadline adjustment that assumes 60Hz, to be used in
     53 // cases where a good estimated draw time is not known. Using 1/3 of the vsync
     54 // as the default adjustment gives the Browser the last 1/3 of a frame to
     55 // produce output, the Renderer Impl thread the middle 1/3 of a frame to produce
     56 // ouput, and the Renderer Main thread the first 1/3 of a frame to produce
     57 // output.
     58 base::TimeDelta BeginFrameArgs::DefaultDeadlineAdjustment() {
     59   return base::TimeDelta::FromMicroseconds(-16666 / 3);
     60 }
     61 
     62 base::TimeDelta BeginFrameArgs::DefaultInterval() {
     63   return base::TimeDelta::FromMicroseconds(16666);
     64 }
     65 
     66 base::TimeDelta BeginFrameArgs::DefaultRetroactiveBeginFramePeriod() {
     67   return base::TimeDelta::FromMicroseconds(4444);
     68 }
     69 
     70 }  // namespace cc
     71