Disabled pinch zooming in non-browser Aura windows.

content/public/browser/web_contents_delegate.h

Index: content/public/browser/web_contents_delegate.h
diff --git a/content/public/browser/web_contents_delegate.h b/content/public/browser/web_contents_delegate.h
index 318f35beb62edabc7445841e8f39fd2c1a3858cf..a2db9b93ec190cd8b98db1906f0b7acb03915992 100644
--- a/content/public/browser/web_contents_delegate.h
+++ b/content/public/browser/web_contents_delegate.h
@@ -57,6 +57,7 @@ class Size;
 namespace blink {
 class WebLayer;
 struct WebWindowFeatures;
+class WebGestureEvent;
 }
 
 namespace content {
@@ -271,6 +272,9 @@ class CONTENT_EXPORT WebContentsDelegate {
   // pressed, or a touch-gesture begins).
   virtual void HandlePointerActivate() {}
 
+  virtual bool PreHandleGestureEvent(WebContents* source,
+                                    const blink::WebGestureEvent& event);
+
   virtual void HandleGestureBegin() {}
   virtual void HandleGestureEnd() {}