cc: Simplify SetNeedsBeginFrames code in scheduler.

cc/scheduler/scheduler_state_machine.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/scheduler/scheduler_state_machine.h"
 
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 705 matching lines @@
   // Proactive BeginFrames are bad for the synchronous compositor because we
   // have to draw when we get the BeginFrame and could end up drawing many
   // duplicate frames if our new frame isn't ready in time.
   // To poll for state with the synchronous compositor without having to draw,
   // we rely on ShouldPollForAnticipatedDrawTriggers instead.
   // Synchronous compositor doesn't have a browser.
   DCHECK(!children_need_begin_frames_);
   return BeginFrameNeededToAnimateOrDraw();
 }
 
 bool SchedulerStateMachine::ShouldSetNeedsBeginFrames(

[brianderson, 2015/03/05 22:51:23]

Looks like you can delete this and frame_source_needs_begin_frames now?

[sunnyps, 2015/03/06 00:49:04]

Done. frame_source_needs_begin_frames is a local var not a class member.

     bool frame_source_needs_begin_frames) const {
   bool needs_begin_frame = BeginFrameNeeded();
 
   // Never call SetNeedsBeginFrames if the frame source has the right value.
   if (needs_begin_frame == frame_source_needs_begin_frames)
     return false;
 
   // Always request the BeginFrame immediately if it's needed.
   if (needs_begin_frame)
     return true;
 
-  // Stop requesting BeginFrames after a deadline.
-  if (begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE)
-    return true;
-
-  // Stop requesting BeginFrames immediately when output surface is lost.
-  if (!HasInitializedOutputSurface())
+  // Stop requesting BeginFrames after a deadline or if we are idle
+  if (begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_INSIDE_DEADLINE ||
+      begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_IDLE)
     return true;
 
   return false;
 }
 
 bool SchedulerStateMachine::ShouldPollForAnticipatedDrawTriggers() const {
   // ShouldPollForAnticipatedDrawTriggers is what we use in place of
   // ProactiveBeginFrameWanted when we are using the synchronous
   // compositor.
   if (!SupportsProactiveBeginFrame()) {
@@ skipping 378 matching lines @@
       static_cast<int>(begin_impl_frame_state_),
       static_cast<int>(commit_state_),
       has_pending_tree_ ? 'T' : 'F',
       pending_tree_is_ready_for_activation_ ? 'T' : 'F',
       active_tree_needs_first_draw_ ? 'T' : 'F',
       max_pending_swaps_,
       pending_swaps_);
 }
 
 }  // namespace cc