CrOS: Schedule renderer drawing to hardware vsync.

Before this patch, the renderer scheduled drawing assuming a 60Hz refresh rate
at an arbitrary timebase. With this patch, we send a hardware vsync signal to
the renderer. The timbase is offset slightly so that the browser UI and
renderer do not draw at the same time.

BUG=157223


Review URL: https://chromiumcodereview.appspot.com/12218055

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@183696 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 49 insertions, 7 deletions

diff --git a/ui/aura/bench/bench_main.cc b/ui/aura/bench/bench_main.cc
index a0c3d1c..3daedeb 100644
--- a/ui/aura/bench/bench_main.cc
+++ b/ui/aura/bench/bench_main.cc
@@ -95,7 +95,8 @@ class BenchCompositorObserver : public ui::CompositorObserver {
 
   virtual void OnCompositingDidCommit(ui::Compositor* compositor) OVERRIDE {}
 
-  virtual void OnCompositingStarted(Compositor* compositor) OVERRIDE {}
+  virtual void OnCompositingStarted(Compositor* compositor,
+                                    base::TimeTicks start_time) OVERRIDE {}
 
   virtual void OnCompositingEnded(Compositor* compositor) OVERRIDE {
     if (start_time_.is_null()) {
@@ -121,6 +122,11 @@ class BenchCompositorObserver : public ui::CompositorObserver {
   virtual void OnCompositingLockStateChanged(
       Compositor* compositor) OVERRIDE {}
 
+  virtual void OnUpdateVSyncParameters(ui::Compositor* compositor,
+                                       base::TimeTicks timebase,
+                                       base::TimeDelta interval) OVERRIDE {
+  }
+
   virtual void Draw() {}
 
   int frames() const { return frames_; }
diff --git a/ui/aura/root_window.cc b/ui/aura/root_window.cc
index 4013173..7305ca7 100644
--- a/ui/aura/root_window.cc
+++ b/ui/aura/root_window.cc
@@ -476,7 +476,8 @@ void RootWindow::ScheduleDraw() {
 void RootWindow::OnCompositingDidCommit(ui::Compositor*) {
 }
 
-void RootWindow::OnCompositingStarted(ui::Compositor*) {
+void RootWindow::OnCompositingStarted(ui::Compositor*,
+                                      base::TimeTicks start_time) {
 }
 
 void RootWindow::OnCompositingEnded(ui::Compositor*) {
@@ -499,6 +500,11 @@ void RootWindow::OnCompositingAborted(ui::Compositor*) {
 void RootWindow::OnCompositingLockStateChanged(ui::Compositor*) {
 }
 
+void RootWindow::OnUpdateVSyncParameters(ui::Compositor* compositor,
+                                         base::TimeTicks timebase,
+                                         base::TimeDelta interval) {
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // RootWindow, ui::LayerDelegate implementation:
 
diff --git a/ui/aura/root_window.h b/ui/aura/root_window.h
index 0a54f1a..6102302 100644
--- a/ui/aura/root_window.h
+++ b/ui/aura/root_window.h
@@ -244,10 +244,14 @@ class AURA_EXPORT RootWindow : public ui::CompositorDelegate,
 
   // Overridden from ui::CompositorObserver:
   virtual void OnCompositingDidCommit(ui::Compositor*) OVERRIDE;
-  virtual void OnCompositingStarted(ui::Compositor*) OVERRIDE;
+  virtual void OnCompositingStarted(ui::Compositor*,
+                                    base::TimeTicks start_time) OVERRIDE;
   virtual void OnCompositingEnded(ui::Compositor*) OVERRIDE;
   virtual void OnCompositingAborted(ui::Compositor*) OVERRIDE;
   virtual void OnCompositingLockStateChanged(ui::Compositor*) OVERRIDE;
+  virtual void OnUpdateVSyncParameters(ui::Compositor* compositor,
+                                       base::TimeTicks timebase,
+                                       base::TimeDelta interval) OVERRIDE;
 
   // Overridden from ui::LayerDelegate:
   virtual void OnDeviceScaleFactorChanged(float device_scale_factor) OVERRIDE;
diff --git a/ui/compositor/compositor.cc b/ui/compositor/compositor.cc
index 923d10d..372a039 100644
--- a/ui/compositor/compositor.cc
+++ b/ui/compositor/compositor.cc
@@ -442,6 +442,13 @@ void Compositor::OnSwapBuffersAborted() {
                     OnCompositingAborted(this));
 }
 
+void Compositor::OnUpdateVSyncParameters(base::TimeTicks timebase,
+                                         base::TimeDelta interval) {
+  FOR_EACH_OBSERVER(CompositorObserver,
+                    observer_list_,
+                    OnUpdateVSyncParameters(this, timebase, interval));
+}
+
 void Compositor::willBeginFrame() {
 }
 
@@ -495,9 +502,10 @@ void Compositor::didCommit() {
 }
 
 void Compositor::didCommitAndDrawFrame() {
+  base::TimeTicks start_time = base::TimeTicks::Now();
   FOR_EACH_OBSERVER(CompositorObserver,
                     observer_list_,
-                    OnCompositingStarted(this));
+                    OnCompositingStarted(this, start_time));
 }
 
 void Compositor::didCompleteSwapBuffers() {
diff --git a/ui/compositor/compositor.h b/ui/compositor/compositor.h
index 2352be2..5cc806d 100644
--- a/ui/compositor/compositor.h
+++ b/ui/compositor/compositor.h
@@ -9,6 +9,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
+#include "base/time.h"
 #include "cc/layer_tree_host_client.h"
 #include "ui/compositor/compositor_export.h"
 #include "ui/gfx/native_widget_types.h"
@@ -174,7 +175,8 @@ class COMPOSITOR_EXPORT CompositorLock
 // appropriately transformed texture for each transformed view in the widget's
 // view hierarchy.
 class COMPOSITOR_EXPORT Compositor
-    : NON_EXPORTED_BASE(public cc::LayerTreeHostClient) {
+    : NON_EXPORTED_BASE(public cc::LayerTreeHostClient),
+      public base::SupportsWeakPtr<Compositor> {
  public:
   Compositor(CompositorDelegate* delegate,
              gfx::AcceleratedWidget widget);
@@ -250,6 +252,9 @@ class COMPOSITOR_EXPORT Compositor
   // Signals swap has aborted (e.g. lost context).
   void OnSwapBuffersAborted();
 
+  void OnUpdateVSyncParameters(base::TimeTicks timebase,
+                               base::TimeDelta interval);
+
   // LayerTreeHostClient implementation.
   virtual void willBeginFrame() OVERRIDE;
   virtual void didBeginFrame() OVERRIDE;
diff --git a/ui/compositor/compositor_observer.h b/ui/compositor/compositor_observer.h
index 4157453..ec93988 100644
--- a/ui/compositor/compositor_observer.h
+++ b/ui/compositor/compositor_observer.h
@@ -5,6 +5,7 @@
 #ifndef UI_COMPOSITOR_COMPOSITOR_OBSERVER_H_
 #define UI_COMPOSITOR_COMPOSITOR_OBSERVER_H_
 
+#include "base/time.h"
 #include "ui/compositor/compositor_export.h"
 
 namespace ui {
@@ -25,7 +26,8 @@ class COMPOSITOR_EXPORT CompositorObserver {
 
   // Called when compositing started: it has taken all the layer changes into
   // account and has issued the graphics commands.
-  virtual void OnCompositingStarted(Compositor* compositor) = 0;
+  virtual void OnCompositingStarted(Compositor* compositor,
+                                    base::TimeTicks start_time) = 0;
 
   // Called when compositing completes: the present to screen has completed.
   virtual void OnCompositingEnded(Compositor* compositor) = 0;
@@ -36,6 +38,11 @@ class COMPOSITOR_EXPORT CompositorObserver {
   // Called when the compositor lock state changes.
   virtual void OnCompositingLockStateChanged(Compositor* compositor) = 0;
 
+  // Called when the compositor has received updated VSync parameters.
+  virtual void OnUpdateVSyncParameters(Compositor* compositor,
+                                       base::TimeTicks timebase,
+                                       base::TimeDelta interval) = 0;
+
  protected:
   virtual ~CompositorObserver() {}
 };
diff --git a/ui/compositor/layer_unittest.cc b/ui/compositor/layer_unittest.cc
index c641e8f..1e75c71 100644
--- a/ui/compositor/layer_unittest.cc
+++ b/ui/compositor/layer_unittest.cc
@@ -277,7 +277,8 @@ class TestCompositorObserver : public CompositorObserver {
   virtual void OnCompositingDidCommit(Compositor* compositor) OVERRIDE {
   }
 
-  virtual void OnCompositingStarted(Compositor* compositor) OVERRIDE {
+  virtual void OnCompositingStarted(Compositor* compositor,
+                                    base::TimeTicks start_time) OVERRIDE {
     started_ = true;
   }
 
@@ -292,6 +293,11 @@ class TestCompositorObserver : public CompositorObserver {
   virtual void OnCompositingLockStateChanged(Compositor* compositor) OVERRIDE {
   }
 
+  virtual void OnUpdateVSyncParameters(Compositor* compositor,
+                                       base::TimeTicks timebase,
+                                       base::TimeDelta interval) OVERRIDE {
+  }
+
   bool started_;
   bool ended_;
   bool aborted_;