Resend unconsumed scroll update from guest back to embedder (WebView Scroll Bubble).

content/browser/frame_host/render_widget_host_view_guest.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 "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "cc/surfaces/surface.h"
 #include "cc/surfaces/surface_factory.h"
@@ skipping 611 matching lines @@
     ForwardGestureEventToRenderer(*g_it);
   }
 }
 
 RenderWidgetHostViewBase*
 RenderWidgetHostViewGuest::GetOwnerRenderWidgetHostView() const {
   return static_cast<RenderWidgetHostViewBase*>(
       guest_->GetOwnerRenderWidgetHostView());
 }
 
+void RenderWidgetHostViewGuest::WheelEventAck(
+    const blink::WebMouseWheelEvent& event,
+    InputEventAckState ack_result) {
+  if (ack_result == INPUT_EVENT_ACK_STATE_NOT_CONSUMED)
+    guest_->ResendEventToEmbedder(event);
+}
+
+void RenderWidgetHostViewGuest::GestureEventAck(
+    const blink::WebGestureEvent& event,
+    InputEventAckState ack_result) {
+  bool not_consumed = INPUT_EVENT_ACK_STATE_NOT_CONSUMED == ack_result;
+  // GestureScrollBegin/End are always consumed by the guest, so we only
+  // forward GestureScrollUpdate.
+  if (event.type == blink::WebInputEvent::GestureScrollUpdate && not_consumed)
+    guest_->ResendEventToEmbedder(event);
+}
+
 void RenderWidgetHostViewGuest::OnHandleInputEvent(
     RenderWidgetHostImpl* embedder,
     int browser_plugin_instance_id,
     const gfx::Rect& guest_window_rect,
     const blink::WebInputEvent* event) {
   if (blink::WebInputEvent::isMouseEventType(event->type)) {
     // The mouse events for BrowserPlugin are modified by all
     // the CSS transforms applied on the <object> and embedder. As a result of
     // this, the coordinates passed on to the guest renderer are potentially
     // incorrect to determine the position of the context menu(they are not the
@@ skipping 34 matching lines @@
       embedder->GetView()->Focus();
     }
 
     host_->ForwardTouchEventWithLatencyInfo(
         *static_cast<const blink::WebTouchEvent*>(event),
         ui::LatencyInfo());
     return;
   }
 
   if (blink::WebInputEvent::isGestureEventType(event->type)) {
-    host_->ForwardGestureEvent(
-        *static_cast<const blink::WebGestureEvent*>(event));
+    const blink::WebGestureEvent& gesture_event =
+        *static_cast<const blink::WebGestureEvent*>(event);
+
+    // We don't forward innertial GestureScrollUpdates to the guest anymore

[Charlie Reis, 2015/09/18 04:30:36]

nit: inertial

[wjmaclean, 2015/09/18 15:30:57]

Done.

+    // since it now receives GestureFlingStart and will have its own fling
+    // curve generating GestureScrollUpdate events for it.
+    // TODO(wjmaclean): Should we try to avoid creating a fling curve in the
+    // embedder renderer in this case? BrowserPlugin can return 'true' for
+    // handleInputEvent() on a GestureFlingStart, and we could use this as
+    // a signal to let the guest handle the fling, though we'd need to be
+    // sure other plugins would behave appropriately (i.e. return 'false').
+    if (gesture_event.type == blink::WebInputEvent::GestureScrollUpdate &&
+        gesture_event.data.scrollUpdate.inertial) {
+      return;
+    }
+    host_->ForwardGestureEvent(gesture_event);
     return;
   }
 }
 
 }  // namespace content