Disabled pinch zooming in non-browser Aura windows.

ui/keyboard/keyboard_controller_proxy.cc

Index: ui/keyboard/keyboard_controller_proxy.cc
diff --git a/ui/keyboard/keyboard_controller_proxy.cc b/ui/keyboard/keyboard_controller_proxy.cc
index fb6f04d9edeffb08e53a01d112e563bd3e0e7156..1f40aad31f3010af13994df2a11acca13c7f144e 100644
--- a/ui/keyboard/keyboard_controller_proxy.cc
+++ b/ui/keyboard/keyboard_controller_proxy.cc
@@ -13,6 +13,7 @@
 #include "content/public/browser/web_contents_view.h"
 #include "content/public/browser/web_ui.h"
 #include "content/public/common/bindings_policy.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/aura/layout_manager.h"
 #include "ui/aura/window.h"
 #include "ui/keyboard/keyboard_constants.h"
@@ -95,6 +96,14 @@ class KeyboardContentsDelegate : public content::WebContentsDelegate,
       const content::MediaResponseCallback& callback) OVERRIDE {
     proxy_->RequestAudioInput(web_contents, request, callback);
   }
+  virtual bool PreHandleGestureEvent(
+      content::WebContents* source,
+      const blink::WebGestureEvent& event) OVERRIDE {
+    // Disable pinch zooming.
+    return event.type == blink::WebGestureEvent::GesturePinchBegin ||
+        event.type == blink::WebGestureEvent::GesturePinchUpdate ||
+        event.type == blink::WebGestureEvent::GesturePinchEnd;
+  }
 
 
   // Overridden from content::WebContentsObserver: