[WebView] Add a new flushVisualState API to AwContents.

content/renderer/render_frame_impl.cc

Index: content/renderer/render_frame_impl.cc
diff --git a/content/renderer/render_frame_impl.cc b/content/renderer/render_frame_impl.cc
index 876e8aef4049d58953e934bbce0bb9cfccad4cae..d4dc49af4c17cf4f90828c98d9355802866a602b 100644
--- a/content/renderer/render_frame_impl.cc
+++ b/content/renderer/render_frame_impl.cc
@@ -1030,6 +1030,8 @@ bool RenderFrameImpl::OnMessageReceived(const IPC::Message& msg) {
                         OnJavaScriptExecuteRequest)
     IPC_MESSAGE_HANDLER(FrameMsg_JavaScriptExecuteRequestForTests,
                         OnJavaScriptExecuteRequestForTests)
+    IPC_MESSAGE_HANDLER(FrameMsg_FlushVisualStateRequest,
+                        OnFlushVisualStateRequest)
     IPC_MESSAGE_HANDLER(FrameMsg_SetEditableSelectionOffsets,
                         OnSetEditableSelectionOffsets)
     IPC_MESSAGE_HANDLER(FrameMsg_SetupTransitionView, OnSetupTransitionView)
@@ -1498,6 +1500,12 @@ void RenderFrameImpl::HandleJavascriptExecutionResult(
   }
 }
 
+void RenderFrameImpl::OnFlushVisualStateRequest(uint64 id) {
+  GetRenderWidget()->QueueMessage(
+      new FrameHostMsg_FlushVisualStateResponse(routing_id_, id),
+      MESSAGE_DELIVERY_POLICY_WITH_VISUAL_STATE);
+}
+
 void RenderFrameImpl::OnSetEditableSelectionOffsets(int start, int end) {
   base::AutoReset<bool> handling_select_range(&handling_select_range_, true);
   if (!GetRenderWidget()->ShouldHandleImeEvent())