overscroll: Make sure the overscroll gesture interacts properly with touch events.

Touch events can arrive during an overscroll gesture initiated by
touch-scrolling. These events should not reset the overscroll state, should
not be sent to the renderer, and should not be in the touch-event queue awaiting
an ACK.

BUG=160668

Review URL: https://codereview.chromium.org/11316056

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@168345 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 6 insertions, 2 deletions

diff --git a/content/browser/renderer_host/overscroll_controller.cc b/content/browser/renderer_host/overscroll_controller.cc
index ce23b17d..0374671 100644
--- a/content/browser/renderer_host/overscroll_controller.cc
+++ b/content/browser/renderer_host/overscroll_controller.cc
@@ -114,7 +114,9 @@ bool OverscrollController::DispatchEventResetsState(
       return false;
 
     default:
-      return true;
+      // Touch events can arrive during an overscroll gesture initiated by
+      // touch-scrolling. These events should not reset the overscroll state.
+      return !WebKit::WebInputEvent::isTouchEventType(event.type);
   }
 }
 
@@ -160,7 +162,9 @@ void OverscrollController::ProcessEventForOverscroll(
     }
 
     default:
-      DCHECK(WebKit::WebInputEvent::isGestureEventType(event.type));
+      DCHECK(WebKit::WebInputEvent::isGestureEventType(event.type) ||
+             WebKit::WebInputEvent::isTouchEventType(event.type))
+          << "Received unexpected event: " << event.type;
   }
 }