touch: Fix touch-event hit-testing for multiple touch points.

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 9c8cf7d1ab64394d29f04b2fb05a86b2a3193b83..09b1e978426778ff98128a15e7e648efcd58bc10 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -97,6 +97,7 @@ using blink::WebScreenInfo;
 using blink::WebSize;
 using blink::WebTextDirection;
 using blink::WebTouchEvent;
+using blink::WebTouchPoint;
 using blink::WebVector;
 using blink::WebWidget;
 
@@ -1115,9 +1116,17 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
   if (!processed &&  input_event->type == WebInputEvent::TouchStart) {
     const WebTouchEvent& touch_event =
         *static_cast<const WebTouchEvent*>(input_event);
-    ack_result = HasTouchEventHandlersAt(touch_event.touches[0].position) ?
-        INPUT_EVENT_ACK_STATE_NOT_CONSUMED :
-        INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
+    // Hit-test for all the pressed touch points. If there is a touch-handler
+    // for any of the touch points, then the renderer should continue to receive
+    // touch events.
+    ack_result = INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS;
+    for (unsigned i = 0; i < touch_event.touchesLength; ++i) {
+      if (touch_event.touches[i].state == WebTouchPoint::StatePressed &&
+          HasTouchEventHandlersAt(touch_event.touches[i].position)) {
+        ack_result = INPUT_EVENT_ACK_STATE_NOT_CONSUMED;
+        break;
+      }
+    }
   }
 
   IPC::Message* response =