cc: Make scheduling be driven by vsync for android webview.

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 76affb9aa21cdf1e2ed9d418ab125deb2f07ac72..6534fe653eed04b8ee26627b869721eb833d6f04 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -778,7 +778,6 @@ void RenderWidgetHostViewAndroid::OnDidChangeBodyBackgroundColor(
 }
 
 void RenderWidgetHostViewAndroid::OnSetNeedsBeginFrames(bool enabled) {
-  DCHECK(using_browser_compositor_);
   TRACE_EVENT1("cc", "RenderWidgetHostViewAndroid::OnSetNeedsBeginFrames",
                "enabled", enabled);
   if (enabled)
@@ -1531,10 +1530,6 @@ void RenderWidgetHostViewAndroid::RemoveLayers() {
 }
 
 void RenderWidgetHostViewAndroid::RequestVSyncUpdate(uint32 requests) {
-  // The synchronous compositor does not requre BeginFrame messages.
-  if (!using_browser_compositor_)
-    requests &= FLUSH_INPUT;
-
   bool should_request_vsync = !outstanding_vsync_requests_ && requests;
   outstanding_vsync_requests_ |= requests;
 
@@ -1582,15 +1577,25 @@ void RenderWidgetHostViewAndroid::SendBeginFrame(base::TimeTicks frame_time,
                                                  base::TimeDelta vsync_period) {
   TRACE_EVENT1("cc", "RenderWidgetHostViewAndroid::SendBeginFrame",
                "frame_time_us", frame_time.ToInternalValue());
-  base::TimeTicks display_time = frame_time + vsync_period;
 
-  base::TimeTicks deadline =
-      display_time - host_->GetEstimatedBrowserCompositeTime();
+  if (using_browser_compositor_) {
+    base::TimeTicks display_time = frame_time + vsync_period;
+
+    base::TimeTicks deadline =
+        display_time - host_->GetEstimatedBrowserCompositeTime();
+
+    host_->Send(new ViewMsg_BeginFrame(
+        host_->GetRoutingID(),
+        cc::BeginFrameArgs::Create(BEGINFRAME_FROM_HERE, frame_time, deadline,
+                                   vsync_period, cc::BeginFrameArgs::NORMAL)));
+  } else {
+    SynchronousCompositorImpl* compositor = SynchronousCompositorImpl::FromID(

[jdduke (slow), 2015/04/01 16:01:14]

Hmm, the other places we use SynchronousCompositorImpl we always check for null.
Should we be doing that here as well?

[sunnyps, 2015/04/01 19:53:02]

Done.

+        host_->GetProcess()->GetID(), host_->GetRoutingID());
 

[jdduke (slow), 2015/04/01 16:01:15]

Can you add a note here briefly mentioning why the SynchronousCompositor doesn't
use the deadline?

[sunnyps, 2015/04/01 19:53:02]

Done.

-  host_->Send(new ViewMsg_BeginFrame(
-      host_->GetRoutingID(),
-      cc::BeginFrameArgs::Create(BEGINFRAME_FROM_HERE, frame_time, deadline,
-                                 vsync_period, cc::BeginFrameArgs::NORMAL)));
+    compositor->SendBeginFrame(cc::BeginFrameArgs::Create(

[jdduke (slow), 2015/04/01 16:01:15]

I'm sure this has already been covered, but why is this called |SendBeginFrame|
instead of just |BeginFrame|?

[sunnyps, 2015/04/01 19:53:01]

Done.

+        BEGINFRAME_FROM_HERE, frame_time, base::TimeTicks(), vsync_period,
+        cc::BeginFrameArgs::NORMAL));
+  }
 }
 
 bool RenderWidgetHostViewAndroid::Animate(base::TimeTicks frame_time) {
@@ -1925,19 +1930,21 @@ void RenderWidgetHostViewAndroid::OnVSync(base::TimeTicks frame_time,
   if (!host_ || host_->is_hidden())
     return;
 
-  const uint32 current_vsync_requests = outstanding_vsync_requests_;
-  outstanding_vsync_requests_ = 0;
-
-  if (current_vsync_requests & FLUSH_INPUT)
+  if (outstanding_vsync_requests_ & FLUSH_INPUT) {
+    outstanding_vsync_requests_ &= ~FLUSH_INPUT;
     host_->FlushInput();
+  }
 
-  if (current_vsync_requests & BEGIN_FRAME ||
-      current_vsync_requests & PERSISTENT_BEGIN_FRAME) {
+  if (outstanding_vsync_requests_ & BEGIN_FRAME ||
+      outstanding_vsync_requests_ & PERSISTENT_BEGIN_FRAME) {
+    outstanding_vsync_requests_ &= ~BEGIN_FRAME;
     SendBeginFrame(frame_time, vsync_period);
   }
 
-  if (current_vsync_requests & PERSISTENT_BEGIN_FRAME)
-    RequestVSyncUpdate(PERSISTENT_BEGIN_FRAME);
+  // This allows for SendBeginFrame to modify outstanding_vsync_requests.

[jdduke (slow), 2015/04/01 16:01:14]

"allows for SendBeginFrame and FlushInput"

[sunnyps, 2015/04/01 19:53:02]

Done.

+  uint32 outstanding_vsync_requests = outstanding_vsync_requests_;
+  outstanding_vsync_requests_ = 0;
+  RequestVSyncUpdate(outstanding_vsync_requests);
 }
 
 void RenderWidgetHostViewAndroid::OnAnimate(base::TimeTicks begin_frame_time) {