cc: Implement unified BeginFrame on aura

ui/compositor/compositor.cc

Index: ui/compositor/compositor.cc
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 287eaf19751ffc5e0d4f4fe09826482f812fef7c..e9af84d0994fee8e1f4bbe6272fd1ebf06265d7b 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -26,7 +26,6 @@
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/compositor/compositor_observer.h"
 #include "ui/compositor/compositor_switches.h"
-#include "ui/compositor/compositor_vsync_manager.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animator_collection.h"
@@ -72,7 +71,6 @@ Compositor::Compositor(gfx::AcceleratedWidget widget,
       widget_(widget),
       surface_id_allocator_(context_factory->CreateSurfaceIdAllocator()),
       task_runner_(task_runner),
-      vsync_manager_(new CompositorVSyncManager()),
       device_scale_factor_(0.0f),
       last_started_frame_(0),
       last_ended_frame_(0),
@@ -95,6 +93,9 @@ Compositor::Compositor(gfx::AcceleratedWidget widget,
   settings.main_frame_before_activation_enabled = false;
   settings.throttle_frame_production =
       !command_line->HasSwitch(switches::kDisableGpuVsync);
+#if defined(USE_AURA)
+  settings.forward_begin_frames_to_children = true;

[brianderson, 2015/03/02 22:38:16]

This flag doesn't seem useful like we thought it would be. Just get rid of it?

Followup patch is fine, but please open a new issue.

[simonhong, 2015/03/03 22:54:12]

Yep, setting state_machine.SetChildrenNeedBeginFrames() is sufficient.
Removed.

+#endif
 #if !defined(OS_MACOSX)
   settings.renderer_settings.partial_swap_enabled =
       !command_line->HasSwitch(cc::switches::kUIDisablePartialSwap);
@@ -153,6 +154,8 @@ Compositor::~Compositor() {
   FOR_EACH_OBSERVER(CompositorObserver, observer_list_,
                     OnCompositingShuttingDown(this));
 
+  DCHECK(!begin_frame_observer_list_.might_have_observers());
+
   if (root_layer_)
     root_layer_->SetCompositor(NULL);
 
@@ -249,8 +252,9 @@ bool Compositor::IsVisible() {
   return host_->visible();
 }
 
-scoped_refptr<CompositorVSyncManager> Compositor::vsync_manager() const {
-  return vsync_manager_;
+void Compositor::SetAuthoritativeVSyncInterval(
+    const base::TimeDelta& interval) {
+  host_->SetAuthoritativeVSyncInterval(interval);
 }
 
 void Compositor::AddObserver(CompositorObserver* observer) {
@@ -280,6 +284,31 @@ bool Compositor::HasAnimationObserver(
   return animation_observer_list_.HasObserver(observer);
 }
 
+void Compositor::AddBeginFrameObserver(

[brianderson, 2015/03/02 22:38:17]

Please add unit tests for this since the last_begin_frame_args_sent_to_observer
logic is hard to get right.

+    CompositorBeginFrameObserver* observer,
+    const cc::BeginFrameArgs& last_begin_frame_args_sent_to_observer) {
+  // If |last_begin_frame_args_| is still effective, send it to the new
+  // |observer| immediately.
+  if (!last_begin_frame_args_sent_to_observer.deadline.is_null() &&

[brianderson, 2015/03/02 22:38:16]

Is this check for a null deadline necessary?

[simonhong, 2015/03/03 22:54:12]

I also can't remember why I added this a while ago. ;)
Removed.

+      last_begin_frame_args_sent_to_observer != missed_begin_frame_args_) {

[brianderson, 2015/03/02 22:38:16]

It is possible that last_begin_frame_args_sent_to_observer.type and 
missed_begin_frame_args_.type are not equal even though they are otherwise
equal.

Can you compare the frame_time's instead so that the type doesn't mess us up?

[simonhong, 2015/03/03 22:54:12]

Done.

+    missed_begin_frame_args_.type = cc::BeginFrameArgs::MISSED;

[brianderson, 2015/03/02 22:38:17]

Can you move this line to the end of Compositor::SendBeginFramesToChildren?

[simonhong, 2015/03/03 22:54:12]

Done.

+    observer->OnSendBeginFrame(missed_begin_frame_args_);
+  }
+
+  if (!begin_frame_observer_list_.might_have_observers())
+    SetChildrenNeedBeginFrames(true);
+  begin_frame_observer_list_.AddObserver(observer);
+}
+
+void Compositor::RemoveBeginFrameObserver(
+    CompositorBeginFrameObserver* observer) {
+  DCHECK(begin_frame_observer_list_.HasObserver(observer));
+  begin_frame_observer_list_.RemoveObserver(observer);
+
+  if (!begin_frame_observer_list_.might_have_observers())
+    SetChildrenNeedBeginFrames(false);
+}
+
 void Compositor::BeginMainFrame(const cc::BeginFrameArgs& args) {
   FOR_EACH_OBSERVER(CompositorAnimationObserver,
                     animation_observer_list_,
@@ -340,6 +369,13 @@ void Compositor::DidAbortSwapBuffers() {
                     OnCompositingAborted(this));
 }
 
+void Compositor::SendBeginFramesToChildren(const cc::BeginFrameArgs& args) {
+  FOR_EACH_OBSERVER(CompositorBeginFrameObserver,
+                    begin_frame_observer_list_,
+                    OnSendBeginFrame(args));
+  missed_begin_frame_args_ = args;
+}
+
 const cc::LayerTreeDebugState& Compositor::GetLayerTreeDebugState() const {
   return host_->debug_state();
 }
@@ -378,4 +414,8 @@ void Compositor::CancelCompositorLock() {
     compositor_lock_->CancelLock();
 }
 
+void Compositor::SetChildrenNeedBeginFrames(bool need_begin_frames) {
+  host_->SetChildrenNeedBeginFrames(need_begin_frames);
+}
+
 }  // namespace ui