Disabled pinch zooming in non-browser Aura windows.

chrome/browser/extensions/extension_host.cc

Index: chrome/browser/extensions/extension_host.cc
diff --git a/chrome/browser/extensions/extension_host.cc b/chrome/browser/extensions/extension_host.cc
index c731e18cd3c225f1d6db79f85b328bf90337a4c3..9ed32ddb2bcfdb127418d12209a9ba28ccefb041 100644
--- a/chrome/browser/extensions/extension_host.cc
+++ b/chrome/browser/extensions/extension_host.cc
@@ -47,6 +47,7 @@
 #include "extensions/common/extension_urls.h"
 #include "extensions/common/feature_switch.h"
 #include "extensions/common/manifest_handlers/background_info.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/window_open_disposition.h"
 
@@ -477,4 +478,13 @@ void ExtensionHost::RequestMediaAccessPermission(
       web_contents, request, callback, extension());
 }
 
+bool ExtensionHost::PreHandleGestureEvent(
+    content::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 extensions