cc: Handle retroactive BeginFrames in the 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/debug/trace_event.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
@@ skipping 168 matching lines @@
   major_state->SetString(
       "forced_redraw_state",
       ForcedRedrawOnTimeoutStateToString(forced_redraw_state_));
   major_state->SetString("readback_state",
                          SynchronousReadbackStateToString(readback_state_));
   state->Set("major_state", major_state.release());
 
   scoped_ptr<base::DictionaryValue> timestamps_state(new base::DictionaryValue);
   base::TimeTicks now = gfx::FrameTime::Now();
   timestamps_state->SetDouble(
-      "0_interval",
-      last_begin_impl_frame_args_.interval.InMicroseconds() / 1000.0L);
+      "0_interval", begin_impl_frame_args_.interval.InMicroseconds() / 1000.0L);
   timestamps_state->SetDouble(
       "1_now_to_deadline",
-      (last_begin_impl_frame_args_.deadline - now).InMicroseconds() / 1000.0L);
+      (begin_impl_frame_args_.deadline - now).InMicroseconds() / 1000.0L);
   timestamps_state->SetDouble(
       "2_frame_time_to_now",
-      (now - last_begin_impl_frame_args_.frame_time).InMicroseconds() /
-          1000.0L);
+      (now - begin_impl_frame_args_.frame_time).InMicroseconds() / 1000.0L);
   timestamps_state->SetDouble(
       "3_frame_time_to_deadline",
-      (last_begin_impl_frame_args_.deadline -
-              last_begin_impl_frame_args_.frame_time).InMicroseconds() /
+      (begin_impl_frame_args_.deadline - begin_impl_frame_args_.frame_time)
+              .InMicroseconds() /
           1000.0L);
   timestamps_state->SetDouble(
       "4_now", (now - base::TimeTicks()).InMicroseconds() / 1000.0L);
   timestamps_state->SetDouble(
       "5_frame_time",
-      (last_begin_impl_frame_args_.frame_time - base::TimeTicks())
-              .InMicroseconds() /
+      (begin_impl_frame_args_.frame_time - base::TimeTicks()).InMicroseconds() /
           1000.0L);
   timestamps_state->SetDouble(
       "6_deadline",
-      (last_begin_impl_frame_args_.deadline - base::TimeTicks())
-              .InMicroseconds() /
+      (begin_impl_frame_args_.deadline - base::TimeTicks()).InMicroseconds() /
           1000.0L);
   state->Set("major_timestamps_in_ms", timestamps_state.release());
 
   scoped_ptr<base::DictionaryValue> minor_state(new base::DictionaryValue);
   minor_state->SetInteger("commit_count", commit_count_);
   minor_state->SetInteger("current_frame_number", current_frame_number_);
 
   minor_state->SetInteger("last_frame_number_swap_performed",
                           last_frame_number_swap_performed_);
   minor_state->SetInteger(
@@ skipping 229 matching lines @@
   // We want to start the first commit after we get a new output surface ASAP.
   if (output_surface_state_ == OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT)
     return true;
 
   // We should not send BeginMainFrame while we are in
   // BEGIN_IMPL_FRAME_STATE_IDLE since we might have new
   // user input arriving soon.
   // TODO(brianderson): Allow sending BeginMainFrame while idle when the main
   // thread isn't consuming user input.
   if (begin_impl_frame_state_ == BEGIN_IMPL_FRAME_STATE_IDLE &&
-      BeginImplFrameNeeded())
+      BeginFrameNeeded())
     return false;
 
   // We need a new commit for the forced redraw. This honors the
   // single commit per interval because the result will be swapped to screen.
   if (forced_redraw_state_ == FORCED_REDRAW_STATE_WAITING_FOR_COMMIT)
     return true;
 
   // After this point, we only start a commit once per frame.
   if (HasSentBeginMainFrameThisFrame())
     return false;
@@ skipping 286 matching lines @@
 }
 
 void SchedulerStateMachine::UpdateStateOnManageTiles() {
   needs_manage_tiles_ = false;
 }
 
 void SchedulerStateMachine::SetSkipNextBeginMainFrameToReduceLatency() {
   skip_next_begin_main_frame_to_reduce_latency_ = true;
 }
 
-bool SchedulerStateMachine::BeginImplFrameNeeded() const {
-  // Proactive BeginImplFrames are bad for the synchronous compositor because we
-  // have to draw when we get the BeginImplFrame and could end up drawing many
+bool SchedulerStateMachine::BeginFrameNeeded() const {
+  // 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.
-  if (!SupportsProactiveBeginImplFrame())
-    return BeginImplFrameNeededToDraw();
+  if (!SupportsProactiveBeginFrame())
+    return BeginFrameNeededToDraw();
 
-  return BeginImplFrameNeededToDraw() ||
-         ProactiveBeginImplFrameWanted();
+  return BeginFrameNeededToDraw() || ProactiveBeginFrameWanted();
 }
 
 bool SchedulerStateMachine::ShouldPollForAnticipatedDrawTriggers() const {
   // ShouldPollForAnticipatedDrawTriggers is what we use in place of
-  // ProactiveBeginImplFrameWanted when we are using the synchronous
+  // ProactiveBeginFrameWanted when we are using the synchronous
   // compositor.
-  if (!SupportsProactiveBeginImplFrame()) {
-    return !BeginImplFrameNeededToDraw() &&
-           ProactiveBeginImplFrameWanted();
+  if (!SupportsProactiveBeginFrame()) {
+    return !BeginFrameNeededToDraw() && ProactiveBeginFrameWanted();
   }
 
   // Non synchronous compositors should rely on
-  // ProactiveBeginImplFrameWanted to poll for state instead.
+  // ProactiveBeginFrameWanted to poll for state instead.
   return false;
 }
 
-bool SchedulerStateMachine::SupportsProactiveBeginImplFrame() const {
+bool SchedulerStateMachine::SupportsProactiveBeginFrame() const {
   // Both the synchronous compositor and disabled vsync settings
   // make it undesirable to proactively request BeginImplFrames.
   // If this is true, the scheduler should poll.
   return !settings_.using_synchronous_renderer_compositor &&
          settings_.throttle_frame_production;
 }
 
 // These are the cases where we definitely (or almost definitely) have a
 // new frame to draw and can draw.
-bool SchedulerStateMachine::BeginImplFrameNeededToDraw() const {
+bool SchedulerStateMachine::BeginFrameNeededToDraw() const {
   // The output surface is the provider of BeginImplFrames, so we are not going
   // to get them even if we ask for them.
   if (!HasInitializedOutputSurface())
     return false;
 
   // If we can't draw, don't tick until we are notified that we can draw again.
   if (!can_draw_)
     return false;
 
   // The forced draw respects our normal draw scheduling, so we need to
@@ skipping 10 matching lines @@
   // additional visible tiles.
   if (swap_used_incomplete_tile_)
     return true;
 
   return needs_redraw_;
 }
 
 // These are cases where we are very likely to draw soon, but might not
 // actually have a new frame to draw when we receive the next BeginImplFrame.
 // Proactively requesting the BeginImplFrame helps hide the round trip latency
-// of the SetNeedsBeginImplFrame request that has to go to the Browser.
-bool SchedulerStateMachine::ProactiveBeginImplFrameWanted() const {
+// of the SetNeedsBeginFrame request that has to go to the Browser.
+bool SchedulerStateMachine::ProactiveBeginFrameWanted() const {
   // The output surface is the provider of BeginImplFrames,
   // so we are not going to get them even if we ask for them.
   if (!HasInitializedOutputSurface())
     return false;
 
   // Do not be proactive when invisible.
   if (!visible_)
     return false;
 
   // We should proactively request a BeginImplFrame if a commit is pending
   // because we will want to draw if the commit completes quickly.
   if (needs_commit_ || commit_state_ != COMMIT_STATE_IDLE)
     return true;
 
   // If the pending tree activates quickly, we'll want a BeginImplFrame soon
   // to draw the new active tree.
   if (has_pending_tree_)
     return true;
 
   // Changing priorities may allow us to activate (given the new priorities),
   // which may result in a new frame.
   if (needs_manage_tiles_)
     return true;
 
   // If we just swapped, it's likely that we are going to produce another
   // frame soon. This helps avoid negative glitches in our
-  // SetNeedsBeginImplFrame requests, which may propagate to the BeginImplFrame
+  // SetNeedsBeginFrame requests, which may propagate to the BeginImplFrame
   // provider and get sampled at an inopportune time, delaying the next
   // BeginImplFrame.
   if (last_frame_number_swap_performed_ == current_frame_number_)
     return true;
 
   return false;
 }
 
 void SchedulerStateMachine::OnBeginImplFrame(const BeginFrameArgs& args) {
   AdvanceCurrentFrameNumber();
-  last_begin_impl_frame_args_ = args;
+  begin_impl_frame_args_ = args;
   DCHECK_EQ(begin_impl_frame_state_, BEGIN_IMPL_FRAME_STATE_IDLE) << *AsValue();
   begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING;
 }
 
 void SchedulerStateMachine::OnBeginImplFrameDeadlinePending() {
   DCHECK_EQ(begin_impl_frame_state_,
             BEGIN_IMPL_FRAME_STATE_BEGIN_FRAME_STARTING)
       << *AsValue();
   begin_impl_frame_state_ = BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME;
 }
@@ skipping 271 matching lines @@
     case OUTPUT_SURFACE_ACTIVE:
     case OUTPUT_SURFACE_WAITING_FOR_FIRST_COMMIT:
     case OUTPUT_SURFACE_WAITING_FOR_FIRST_ACTIVATION:
       return true;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace cc