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

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 2165 matching lines @@
         return true;
 
     // Unhandled touchpad gesture pinch events synthesize mouse wheel events.
     if (inputEvent.type == WebInputEvent::GesturePinchUpdate) {
         const WebGestureEvent& pinchEvent = static_cast<const WebGestureEvent&>(inputEvent);
 
         // First, synthesize a Windows-like wheel event to send to any handlers that may exist.
         if (handleSyntheticWheelFromTouchpadPinchEvent(pinchEvent))
             return true;
 
+        if (pinchEvent.data.pinchUpdate.zoomDisabled)
+            return false;

[ccameron, 2015/05/06 03:48:32]

Testing for this requires event sender support from the Chromium side.

+
         if (page()->frameHost().pinchViewport().magnifyScaleAroundAnchor(pinchEvent.data.pinchUpdate.scale, FloatPoint(pinchEvent.x, pinchEvent.y)))
             return true;
     }
 
     return false;
 }
 
 void WebViewImpl::setCursorVisibilityState(bool isVisible)
 {
     if (m_page)
@@ skipping 2270 matching lines @@
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 void WebViewImpl::forceNextWebGLContextCreationToFail()
 {
     WebGLRenderingContext::forceNextWebGLContextCreationToFail();
 }
 
 } // namespace blink