Filter GestureFlingStarts with Vx=Vy=0 in RenderWidgetHostViewChildFrame

content/browser/frame_host/render_widget_host_view_child_frame.cc

 // Copyright 2014 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/browser/frame_host/render_widget_host_view_child_frame.h"
 
 #include <algorithm>
 #include <utility>
 #include <vector>
 
@@ skipping 15 matching lines @@
 #include "content/browser/gpu/compositor_util.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_delegate.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_input_event_router.h"
 #include "content/common/text_input_state.h"
 #include "content/common/view_messages.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/common/browser_plugin_guest_mode.h"
 #include "gpu/ipc/common/gpu_messages.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/gfx/geometry/size_conversions.h"
 #include "ui/gfx/geometry/size_f.h"
 
 namespace content {
 
 RenderWidgetHostViewChildFrame::RenderWidgetHostViewChildFrame(
     RenderWidgetHost* widget_host)
     : host_(RenderWidgetHostImpl::From(widget_host)),
       next_surface_sequence_(1u),
       last_output_surface_id_(0),
@@ skipping 602 matching lines @@
 
   observing_begin_frame_source_ = needs_begin_frames;
   if (begin_frame_source_) {
     if (observing_begin_frame_source_)
       begin_frame_source_->AddObserver(this);
     else
       begin_frame_source_->RemoveObserver(this);
   }
 }
 
+InputEventAckState RenderWidgetHostViewChildFrame::FilterInputEvent(
+    const blink::WebInputEvent& input_event) {
+  if (input_event.type == blink::WebInputEvent::GestureFlingStart) {
+    const blink::WebGestureEvent& gesture_event =
+        static_cast<const blink::WebGestureEvent&>(input_event);
+    // Zero-velocity touchpad flings are an Aura-specific signal that the
+    // touchpad scroll has ended, and should not be forwarded to the renderer.
+    if (gesture_event.sourceDevice == blink::WebGestureDeviceTouchpad &&
+        !gesture_event.data.flingStart.velocityX &&
+        !gesture_event.data.flingStart.velocityY) {
+      // Here we indicate that there was no consumer for this event, as
+      // otherwise the fling animation system will try to run an animation
+      // and will also expect a notification when the fling ends. Since
+      // CrOS just uses the GestureFlingStart with zero-velocity as a means
+      // of indicating that touchpad scroll has ended, we don't actually want
+      // a fling animation.
+      // Note: this event handling is modeled on similar code in
+      // TenderWidgetHostViewAura::FilterInputEvent().
+      return INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
+    }
+  }
+
+  return INPUT_EVENT_ACK_STATE_NOT_CONSUMED;
+}
+
 BrowserAccessibilityManager*
 RenderWidgetHostViewChildFrame::CreateBrowserAccessibilityManager(
     BrowserAccessibilityDelegate* delegate, bool for_root_frame) {
   return BrowserAccessibilityManager::Create(
       BrowserAccessibilityManager::GetEmptyDocument(), delegate);
 }
 
 void RenderWidgetHostViewChildFrame::ClearCompositorSurfaceIfNecessary() {
   if (surface_factory_ && !surface_id_.is_null())
     surface_factory_->Destroy(surface_id_);
   surface_id_ = cc::SurfaceId();
 }
 
 bool RenderWidgetHostViewChildFrame::IsChildFrameForTesting() const {
   return true;
 }
 
 cc::SurfaceId RenderWidgetHostViewChildFrame::SurfaceIdForTesting() const {
   return surface_id_;
 };
 
 }  // namespace content