gpu benchmarking swipe for touchpad

content/renderer/gpu/gpu_benchmarking_extension.h

Index: content/renderer/gpu/gpu_benchmarking_extension.h
diff --git a/content/renderer/gpu/gpu_benchmarking_extension.h b/content/renderer/gpu/gpu_benchmarking_extension.h
index 2b69d2b1329b1bb60d2669771ee08bf5498d25a4..d9bd41e59a5961f6d80a12e76a2fa33a61619ea7 100644
--- a/content/renderer/gpu/gpu_benchmarking_extension.h
+++ b/content/renderer/gpu/gpu_benchmarking_extension.h
@@ -48,7 +48,14 @@ class GpuBenchmarking : public gin::Wrappable<GpuBenchmarking> {
   bool GestureSourceTypeSupported(int gesture_source_type);
   bool SmoothScrollBy(gin::Arguments* args);
   bool SmoothDrag(gin::Arguments* args);
+
+  // This function generates a scroll followed by a fling. The default input
+  // source is touch; Source, velocity_x, and velocity_y are extra args that
+  // are necessary for a touchpad fling. Note that the callback function of
+  // swipe will get called only when the GFS is handled by the compositor
+  // thread.

[tdresser, 2017/03/21 19:20:02]

Why will the callback only be called when the GFS is handled on the compositor?

[sahel, 2017/03/22 14:43:25]

I traced back the messages. When the compositor handles the fling, a
notification (DidStopFlinging) calls
RenderWidgetHostImpl::OnSyntheticGestureCompleted(). This function in turn
causes the callback to get executed.

On the other hand when the fling is handled by main thread, there is some
plumbing to notify layer_tree_host_impl that the fling on main is over. But it's
not plumbed to call OnSyntheticGestureCompleted().

[tdresser, 2017/03/22 15:21:29]

Yikes. Can you file a bug for this? Maybe assign it to Lan?

[sahel, 2017/03/22 16:04:04]

Done.

   bool Swipe(gin::Arguments* args);
+
   bool ScrollBounce(gin::Arguments* args);
   bool PinchBy(gin::Arguments* args);
   bool Tap(gin::Arguments* args);