Make Mac pinch thresholding apply only to zoom (Chromium side)

content/renderer/input/input_handler_proxy.cc

 // Copyright 2013 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/renderer/input/input_handler_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
@@ skipping 262 matching lines @@
         input_handler_->PinchGestureEnd();
         return DID_HANDLE;
       } else {
         return DID_NOT_HANDLE;
       }
 
     case WebInputEvent::GesturePinchUpdate: {
       if (gesture_pinch_on_impl_thread_) {
         const WebGestureEvent& gesture_event =
             static_cast<const WebGestureEvent&>(event);
+        if (gesture_event.data.pinchUpdate.zoomDisabled)
+            return DROP_EVENT;
         input_handler_->PinchGestureUpdate(
             gesture_event.data.pinchUpdate.scale,
             gfx::Point(gesture_event.x, gesture_event.y));
         return DID_HANDLE;
       } else {
         return DID_NOT_HANDLE;
       }
     }
 
     case WebInputEvent::GestureFlingStart:
@@ skipping 658 matching lines @@
   // trigger a scroll, e.g., with a trivial time delta between fling updates.
   // Return true in this case to prevent early fling termination.
   if (std::abs(clipped_increment.width) < kScrollEpsilon &&
       std::abs(clipped_increment.height) < kScrollEpsilon)
     return true;
 
   return did_scroll;
 }
 
 }  // namespace content