RenderWidget popup should be a NSWindow so it can go outside the main window.

chrome/browser/chrome_browser_application_mac.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROME_BROWSER_APPLICATION_MAC_H_
 #define CHROME_BROWSER_CHROME_BROWSER_APPLICATION_MAC_H_
 
 #ifdef __OBJC__
 
 #import <AppKit/AppKit.h>
 
 #include <vector>
 
 #import "base/mac/scoped_sending_event.h"
 #import "base/memory/scoped_nsobject.h"
 #import "base/message_pump_mac.h"
 #include "base/synchronization/lock.h"
+#import "ui/base/cocoa/event_hook_application.h"
 
-// Event hooks must implement this protocol.
-@protocol CrApplicationEventHookProtocol
-- (void)hookForEvent:(NSEvent*)theEvent;
-@end
-
-@interface BrowserCrApplication : NSApplication<CrAppProtocol,
-                                                CrAppControlProtocol> {
+@interface BrowserCrApplication : CrEventHookApplication<CrAppProtocol,
+                                                         CrAppControlProtocol> {
  @private
   BOOL handlingSendEvent_;
   BOOL cyclingWindows_;
 
-  // Array of objects implementing CrApplicationEventHookProtocol.
-  scoped_nsobject<NSMutableArray> eventHooks_;
-
   // App's previous key windows. Most recent key window is last.
   // Does not include current key window. Elements of this vector are weak
   // references.
   std::vector<NSWindow*> previousKeyWindows_;
 
   // Guards previousKeyWindows_.
   base::Lock previousKeyWindowsLock_;
 }
 
 // Our implementation of |-terminate:| only attempts to terminate the
 // application, i.e., begins a process which may lead to termination. This
 // method cancels that process.
 - (void)cancelTerminate:(id)sender;
 
-// Add or remove an event hook to be called for every sendEvent:
-// that the application receives.  These handlers are called before
-// the normal [NSApplication sendEvent:] call is made.
-
-// This is not a good alternative to a nested event loop.  It should
-// be used only when normal event logic and notification breaks down
-// (e.g. when clicking outside a canBecomeKey:NO window to "switch
-// context" out of it).
-- (void)addEventHook:(id<CrApplicationEventHookProtocol>)hook;
-- (void)removeEventHook:(id<CrApplicationEventHookProtocol>)hook;
-
 // Keep track of the previous key windows and whether windows are being
 // cycled for use in determining whether a Panel window can become the
 // key window.
 - (NSWindow*)previousKeyWindow;
 - (BOOL)isCyclingWindows;
 @end
 
 namespace chrome_browser_application_mac {
 
 // Bin for unknown exceptions. Exposed for testing purposes.
@@ skipping 18 matching lines @@
 
 // Calls -[NSApp terminate:].
 void Terminate();
 
 // Cancels a termination started by |Terminate()|.
 void CancelTerminate();
 
 }  // namespace chrome_browser_application_mac
 
 #endif  // CHROME_BROWSER_CHROME_BROWSER_APPLICATION_MAC_H_