Make sure manifest specified shortcut for Extension Command can not override the built-in shortcuts.

chrome/browser/ui/cocoa/accelerator_utils_cocoa.mm

+// Copyright (c) 2013 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.
+
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/ui/cocoa/accelerators_cocoa.h"
+#import "chrome/browser/ui/cocoa/browser_window_utils.h"
+#include "content/public/browser/native_web_keyboard_event.h"
+#include "ui/base/accelerators/accelerator.h"
+#import "ui/base/accelerators/platform_accelerator_cocoa.h"
+#import "ui/base/keycodes/keyboard_code_conversion_mac.h"
+
+namespace chrome {
+
+bool IsChromeAccelerator(const ui::Accelerator& accelerator, Profile* profile) {
+  // The |accelerator| passed in contains a Windows key code but no platform
+  // accelerator info. The Accelerator list is the opposite: It has accelerators
+  // that have key_code() == VKEY_UNKNOWN but they contain a platform
+  // accelerator. We find common ground by converting the passed in Windows key
+  // code to a character and use that when comparing against the Accelerator
+  // list.
+  unichar character;
+  unichar characterIgnoringModifiers;
+  ui::MacKeyCodeForWindowsKeyCode(accelerator.key_code(),
+                                  0,
+                                  &character,
+                                  &characterIgnoringModifiers);
+  NSString* characters =
+      [[[NSString alloc] initWithCharacters:&character length:1] autorelease];
+
+  NSUInteger modifiers =
+      (accelerator.IsCtrlDown() ? NSControlKeyMask : 0) |
+      (accelerator.IsCmdDown() ? NSCommandKeyMask : 0) |
+      (accelerator.IsAltDown() ? NSAlternateKeyMask : 0) |
+      (accelerator.IsShiftDown() ? NSShiftKeyMask : 0);
+
+  NSEvent* event = [NSEvent keyEventWithType:NSKeyDown
+                                    location:NSZeroPoint
+                               modifierFlags:modifiers
+                                   timestamp:0
+                                windowNumber:0
+                                     context:nil
+                                  characters:characters
+                 charactersIgnoringModifiers:characters
+                                   isARepeat:NO
+                                     keyCode:accelerator.key_code()];
+
+  content::NativeWebKeyboardEvent keyboard_event(event);
+  int id = [BrowserWindowUtils getCommandId:keyboard_event];
+  if (id != -1)
+    return true;
+
+  AcceleratorsCocoa* accelerators = AcceleratorsCocoa::GetInstance();
+  for (AcceleratorsCocoa::const_iterator iter = accelerators->begin();
+       iter != accelerators->end(); ++iter) {

[Nico, 2013/04/16 21:44:54]

I don't know if the secondary shortcuts should win over extensions shortcuts or
not. For regular keypresses, I think we let web contents win over the secondary
shortcuts but give the browser precedence over the web for the primary shortcuts
(the ones that BrowserWindowUtils categorizes).

Up to you, just fyi.

[Finnur, 2013/04/17 14:28:07]

Good point. We should probably be consistent here.

+    const ui::PlatformAcceleratorCocoa* platform_accelerator =
+        static_cast<const ui::PlatformAcceleratorCocoa*>(
+            iter->second.platform_accelerator());
+    if ([characters isEqualToString:platform_accelerator->characters()] &&
+        modifiers == platform_accelerator->modifier_mask())
+      return true;
+  }
+
+  return false;
+}
+
+}  // namespace chrome