Move synthetic gesture input to be aligned with BeginFrame.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index 5fb48340e8e0d9797cbd848df330f0bc9e38b379..fe65bc1d0651a379c827f89cdeadb5937170cf36 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -440,6 +440,9 @@ RenderWidgetHostViewAura::RenderWidgetHostViewAura(RenderWidgetHost* host,
       has_composition_text_(false),
       accept_return_character_(false),
       begin_frame_source_(nullptr),
+      needs_begin_frames_(false),
+      needs_flush_input_(false),
+      added_frame_observer_(false),
       synthetic_move_sent_(false),
       cursor_visibility_state_in_renderer_(UNKNOWN),
 #if defined(OS_WIN)
@@ -712,10 +715,25 @@ ui::TextInputClient* RenderWidgetHostViewAura::GetTextInputClient() {
 }
 
 void RenderWidgetHostViewAura::SetNeedsBeginFrames(bool needs_begin_frames) {
+  needs_begin_frames_ = needs_begin_frames;
+  UpdateNeedsBeginFramesInternal();
+}
+
+void RenderWidgetHostViewAura::OnSetNeedsFlushInput() {
+  needs_flush_input_ = true;
+  UpdateNeedsBeginFramesInternal();
+}
+
+void RenderWidgetHostViewAura::UpdateNeedsBeginFramesInternal() {
   if (!begin_frame_source_)
     return;
 
-  if (needs_begin_frames)
+  bool needs_frame = needs_begin_frames_ || needs_flush_input_;
+  if (needs_frame == added_frame_observer_)
+    return;
+
+  added_frame_observer_ = needs_frame;
+  if (needs_frame)
     begin_frame_source_->AddObserver(this);
   else
     begin_frame_source_->RemoveObserver(this);
@@ -723,6 +741,9 @@ void RenderWidgetHostViewAura::SetNeedsBeginFrames(bool needs_begin_frames) {
 
 void RenderWidgetHostViewAura::OnBeginFrame(
     const cc::BeginFrameArgs& args) {
+  needs_flush_input_ = false;
+  host_->FlushInput();
+  UpdateNeedsBeginFramesInternal();
   host_->Send(new ViewMsg_BeginFrame(host_->GetRoutingID(), args));
   last_begin_frame_args_ = args;
 }
@@ -2924,12 +2945,12 @@ void RenderWidgetHostViewAura::DelegatedFrameHostOnLostCompositorResources() {
 
 void RenderWidgetHostViewAura::SetBeginFrameSource(
     cc::BeginFrameSource* source) {
-  bool needs_begin_frames = host_->needs_begin_frames();
-  if (begin_frame_source_ && needs_begin_frames)
+  if (begin_frame_source_ && added_frame_observer_) {
     begin_frame_source_->RemoveObserver(this);
+    added_frame_observer_ = false;
+  }
   begin_frame_source_ = source;
-  if (begin_frame_source_ && needs_begin_frames)
-    begin_frame_source_->AddObserver(this);
+  UpdateNeedsBeginFramesInternal();
 }
 
 bool RenderWidgetHostViewAura::IsAutoResizeEnabled() const {