[exp] Browser-side fling.

content/renderer/input/input_handler_proxy.cc

Index: content/renderer/input/input_handler_proxy.cc
diff --git a/content/renderer/input/input_handler_proxy.cc b/content/renderer/input/input_handler_proxy.cc
index d9a34ada63b15efc548b0188ee606161997a3bfb..f5236a9e20c7b186180d0c5818fb77966b1c76ef 100644
--- a/content/renderer/input/input_handler_proxy.cc
+++ b/content/renderer/input/input_handler_proxy.cc
@@ -66,7 +66,9 @@ bool ShouldSuppressScrollForFlingBoosting(
     const gfx::Vector2dF& current_fling_velocity,
     const WebGestureEvent& scroll_update_event,
     double time_since_last_boost_event) {
-  DCHECK_EQ(WebInputEvent::GestureScrollUpdate, scroll_update_event.type);
+  DCHECK(WebInputEvent::GestureScrollUpdate == scroll_update_event.type ||
+         WebInputEvent::GestureScrollUpdateWithoutPropagation ==
+             scroll_update_event.type);
 
   gfx::Vector2dF dx(scroll_update_event.data.scrollUpdate.deltaX,
                     scroll_update_event.data.scrollUpdate.deltaY);
@@ -287,7 +289,9 @@ InputHandlerProxy::EventDisposition InputHandlerProxy::HandleInputEvent(
         NOTREACHED();
         break;
     }
-  } else if (event.type == WebInputEvent::GestureScrollUpdate) {
+  } else if (event.type == WebInputEvent::GestureScrollUpdate ||
+             event.type ==
+                 WebInputEvent::GestureScrollUpdateWithoutPropagation) {
 #ifndef NDEBUG
     DCHECK(expect_scroll_update_end_);
 #endif
@@ -510,6 +514,7 @@ bool InputHandlerProxy::FilterInputEventForFlingBoosting(
       ExtendBoostedFlingTimeout(gesture_event);
       return true;
 
+    case WebInputEvent::GestureScrollUpdateWithoutPropagation:
     case WebInputEvent::GestureScrollUpdate: {
       const double time_since_last_boost_event =
           event.timeStampSeconds - last_fling_boost_event_.timeStampSeconds;
@@ -714,6 +719,8 @@ bool InputHandlerProxy::CancelCurrentFlingWithoutNotifyingClient() {
     WebGestureEvent last_fling_boost_event = last_fling_boost_event_;
     last_fling_boost_event_ = WebGestureEvent();
     if (last_fling_boost_event.type == WebInputEvent::GestureScrollBegin ||
+        last_fling_boost_event.type ==
+            WebInputEvent::GestureScrollUpdateWithoutPropagation ||
         last_fling_boost_event.type == WebInputEvent::GestureScrollUpdate) {
       // Synthesize a GestureScrollBegin, as the original was suppressed.
       HandleInputEvent(ObtainGestureScrollBegin(last_fling_boost_event));