Disabled pinch zooming in non-browser Aura windows.

content/public/browser/web_contents_delegate.cc

Index: content/public/browser/web_contents_delegate.cc
diff --git a/content/public/browser/web_contents_delegate.cc b/content/public/browser/web_contents_delegate.cc
index 63ad65baeabd93980bd423d3078685cb4074f52b..0f7fa48e0f28bd484e597c3b2dd71244679a7a6c 100644
--- a/content/public/browser/web_contents_delegate.cc
+++ b/content/public/browser/web_contents_delegate.cc
@@ -11,6 +11,7 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/url_constants.h"
 #include "content/public/common/bindings_policy.h"
+#include "third_party/WebKit/public/web/WebInputEvent.h"
 #include "ui/gfx/rect.h"
 
 namespace content {
@@ -110,6 +111,19 @@ bool WebContentsDelegate::PreHandleKeyboardEvent(
   return false;
 }
 
+bool WebContentsDelegate::PreHandleGestureEvent(
+    WebContents* source,
+    const blink::WebGestureEvent& event) {
+#if !defined(OS_ANDROID)
+  // On Desktop, swallow pinch events by default

[jam, 2014/01/14 17:02:45]

why is this logic in this interface? will every content embedder want this as
the default?

i'm wondering why this method doesn't just return false always, and places in
chrome that want to disable gesture events can override it and return true.

[bokan, 2014/01/14 18:49:05]

The idea is to disable pinch in all cases except when the content is in the
browser. Native-looking UI shouldn't respond to pinch gestures. From that point
of view I think having the embedder explicitly opt-in to pinches is cleaner, but
I'm happy to change it if you disagree.

[jam, 2014/01/16 16:42:44]

Native looking UI shouldn't be using WebContents, but instead should be using
views etc. Which UI are you talking about?

[bokan, 2014/01/16 16:49:20]

OOBE pages like the login screen, create new user, etc. We also want it disabled
in packaged apps. Sorry, I haven't done much work in Chromium so I'm still
getting the terminology down.

[jam, 2014/01/17 05:49:51]

I see. So why not just have those places override the method and return whatever
value they need? basically we shouldn't put that logic spread across the Browser
callback and here.

+  return event.type == blink::WebGestureEvent::GesturePinchBegin ||
+      event.type == blink::WebGestureEvent::GesturePinchUpdate ||
+      event.type == blink::WebGestureEvent::GesturePinchEnd;
+#else
+  return false;
+#endif
+}
+
 bool WebContentsDelegate::CanDragEnter(
     WebContents* source,
     const DropData& data,