Disabled pinch zooming in non-browser Aura windows.

ui/web_dialogs/web_dialog_web_contents_delegate.cc

 // Copyright (c) 2012 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 "ui/web_dialogs/web_dialog_web_contents_delegate.h"
 
 #include "base/logging.h"
 #include "content/public/browser/web_contents.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 
 using content::BrowserContext;
 using content::OpenURLParams;
 using content::WebContents;
 
 namespace ui {
 
 // Incognito profiles are not long-lived, so we always want to store a
 // non-incognito profile.
 //
@@ skipping 29 matching lines @@
                            initial_pos, user_gesture);
 }
 
 bool WebDialogWebContentsDelegate::IsPopupOrPanel(
     const WebContents* source) const {
   // This needs to return true so that we are allowed to be resized by our
   // contents.
   return true;
 }
 
+bool WebDialogWebContentsDelegate::PreHandleGestureEvent(
+    WebContents* source,
+    const blink::WebGestureEvent& event) {
+  // Disable pinch zooming.
+  return event.type == blink::WebGestureEvent::GesturePinchBegin ||
+      event.type == blink::WebGestureEvent::GesturePinchUpdate ||
+      event.type == blink::WebGestureEvent::GesturePinchEnd;
+}
+
 }  // namespace ui