Android WebView: flush input events during onVSync

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 dd65887f78db5d47ad01b2adc5b5da168d243a18..46c0427313cf0370f34ae29ab51b92739ccea826 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -811,6 +811,12 @@ void RenderWidgetHostViewAndroid::ShowDisambiguationPopup(
 
 scoped_ptr<SyntheticGestureTarget>
 RenderWidgetHostViewAndroid::CreateSyntheticGestureTarget() {
+  DCHECK(content_view_core_);
+  if (using_synchronous_compositor_) {

[boliu, 2014/08/20 21:41:53]

&& !observing_root_window_

I think this should be done in OnSetNeedsFlushInput, where you don't even need
the using_synchronous_compositor_ check

[hush (inactive), 2014/08/20 22:07:32]

I used to think doing this in OnSetNeedsFlushInput will cause webview to
register observer unnecessarily.
In fact, OnSetNeedsFlushInput is not called for webview unless the input comes
from synthetic gestures.
So yes. I will move this part to OnSetNeedsFlushInput.
Thanks!

On 2014/08/20 21:41:53, boliu wrote:

+    content_view_core_->GetWindowAndroid()->AddObserver(this);
+    observing_root_window_ = true;
+  }
+
   return scoped_ptr<SyntheticGestureTarget>(new SyntheticGestureTargetAndroid(
       host_, content_view_core_->CreateTouchEventSynthesizer()));
 }
@@ -1529,6 +1535,9 @@ void RenderWidgetHostViewAndroid::OnVSync(base::TimeTicks frame_time,
     host_->FlushInput();
   }
 
+  if (using_synchronous_compositor_)
+    return;
+
   TRACE_EVENT0("cc", "RenderWidgetHostViewAndroid::SendBeginFrame");
   base::TimeTicks display_time = frame_time + vsync_period;