Respect the order of input messages from browser to renderer

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <memory>
 
@@ skipping 641 matching lines @@
       has_scrolled_focused_editable_node_into_rect_(false),
       page_zoom_level_(params.page_zoom_level),
       main_render_frame_(nullptr),
       frame_widget_(nullptr),
       speech_recognition_dispatcher_(NULL),
       mouse_lock_dispatcher_(NULL),
 #if defined(OS_ANDROID)
       expected_content_intent_id_(0),
 #endif
       enumeration_completion_id_(0),
-      session_storage_namespace_id_(params.session_storage_namespace_id) {
+      session_storage_namespace_id_(params.session_storage_namespace_id),
+      has_added_input_handler_(false) {
   GetWidget()->set_owner_delegate(this);
 }
 
 void RenderViewImpl::Initialize(const ViewMsg_New_Params& params,
                                 bool was_created_by_renderer) {
   SetRoutingID(params.view_id);
 
   int opener_view_routing_id;
   WebFrame* opener_frame = RenderFrameImpl::ResolveOpener(
       params.opener_frame_route_id, &opener_view_routing_id);
@@ skipping 1371 matching lines @@
 
   bool use_threaded_event_handling = true;
 #if defined(OS_MACOSX)
   // Disable threaded event handling if content is not handling the elastic
   // overscroll effect. This includes the cases where the elastic overscroll
   // effect is being handled by Blink (because of command line flags) and older
   // operating system versions which do not have an elastic overscroll effect
   // (SnowLeopard, which has Aqua scrollbars which need synchronous updates).
   use_threaded_event_handling = compositor_deps_->IsElasticOverscrollEnabled();
 #endif
-  if (use_threaded_event_handling) {
-    RenderThreadImpl* render_thread = RenderThreadImpl::current();
-    // render_thread may be NULL in tests.
-    InputHandlerManager* input_handler_manager =
-        render_thread ? render_thread->input_handler_manager() : NULL;
-    if (input_handler_manager) {
-      input_handler_manager->AddInputHandler(
-          GetRoutingID(), rwc->GetInputHandler(), AsWeakPtr(),
-          webkit_preferences_.enable_scroll_animator,
-          UseGestureBasedWheelScrolling());
-    }
+  if (!use_threaded_event_handling)
+    return;
+
+  RenderThreadImpl* render_thread = RenderThreadImpl::current();
+  // render_thread may be NULL in tests.
+  InputHandlerManager* input_handler_manager =
+      render_thread ? render_thread->input_handler_manager() : NULL;
+  if (input_handler_manager) {
+    input_handler_manager->AddInputHandler(
+        GetRoutingID(), rwc->GetInputHandler(), AsWeakPtr(),
+        webkit_preferences_.enable_scroll_animator,
+        UseGestureBasedWheelScrolling());
+    has_added_input_handler_ = true;
   }
 }
 
 bool RenderViewImpl::allowsBrokenNullLayerTreeView() const {
   return RenderWidget::allowsBrokenNullLayerTreeView();
 }
 
 void RenderViewImpl::closeWidgetSoon() {
   RenderWidget::closeWidgetSoon();
 }
@@ skipping 132 matching lines @@
     const blink::WebElement& element) {
   blink::WebRect bounding_box_in_window = element.boundsInViewport();
   ConvertViewportToWindowViaWidget(&bounding_box_in_window);
   return gfx::RectF(bounding_box_in_window);
 }
 
 float RenderViewImpl::GetDeviceScaleFactorForTest() const {
   return device_scale_factor_;
 }
 
+bool RenderViewImpl::HasAddedInputHandler() const {
+  return has_added_input_handler_;
+}
+
 gfx::Point RenderViewImpl::ConvertWindowPointToViewport(
     const gfx::Point& point) {
   blink::WebFloatRect point_in_viewport(point.x(), point.y(), 0, 0);
   convertWindowToViewport(&point_in_viewport);
   return gfx::Point(point_in_viewport.x, point_in_viewport.y);
 }
 
 void RenderViewImpl::didChangeIcon(WebLocalFrame* frame,
                                    WebIconURL::Type icon_type) {
   if (frame->parent())
@@ skipping 1175 matching lines @@
         return render_frame->focused_pepper_plugin();
     }
     frame = frame->traverseNext(false);
   }
 
   return nullptr;
 }
 #endif
 
 }  // namespace content