mac: Load the system hotkeys after launch.

content/browser/cocoa/system_hotkey_helper_mac.h

+// Copyright 2014 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 CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_HELPER_MAC_H_
+#define CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_HELPER_MAC_H_
+
+#include "base/memory/singleton.h"
+#include "base/memory/weak_ptr.h"
+
+#ifdef __OBJC__
+@class NSData;
+#else
+class NSData;
+#endif
+
+namespace content {
+
+class SystemHotkeyMap;
+
+class SystemHotkeyHelperMac {

[Robert Sesek, 2014/07/08 13:40:00]

Does this need to be its own class? It's small enough to just be part of
SystemHotkeyMap.

[erikchen, 2014/07/10 02:07:31]

It would technically be possible to finesse the SystemHotkeyMap class to have no
ObjC in its header file, but it would be ugly. This class also serves the
purpose of having a C++ translation unit safe header file that can invoke ObjC
in its implementation.

+ public:
+  // Return pointer to the singleton instance for the current process.
+  static SystemHotkeyHelperMac* GetInstance();
+
+  // Loads the system hot keys after a brief delay, to reduce file system access
+  // immediately after launch.
+  void DeferredLoadSystemHotkeys();
+
+  // Guaranteed to not be NULL.
+  SystemHotkeyMap* map() { return map_.get(); }
+
+ private:
+  friend struct DefaultSingletonTraits<SystemHotkeyHelperMac>;
+
+  SystemHotkeyHelperMac();
+  virtual ~SystemHotkeyHelperMac();
+
+  // Must be called from the UI thread. Invokes LoadFile from the FILE thread.
+  void LoadSystemHotkeys();
+
+  // Must be called from the FILE thread. Loads the file containing the system
+  // hotkeys into a NSData* object, and passes the result to FileDidLoad on the
+  // UI thread.
+  void LoadFile();
+
+  // Must be called from the UI thread. |data| should have a retain count of
+  // +1. This method will release |data|. Parses the system hotkeys from the
+  // plist stored in |data|.
+  void FileDidLoad(NSData* data);
+
+  scoped_ptr<SystemHotkeyMap> map_;

[Robert Sesek, 2014/07/08 13:40:00]

Any reason this needs to be a pointer instead of just a member?

[erikchen, 2014/07/10 02:07:31]

Yes, for it to be a member, I'd have to move the #include into this file, but
the #include is not safe for C++ translation units, which this file is a part
of.

+  base::WeakPtrFactory<SystemHotkeyHelperMac> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SystemHotkeyHelperMac);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_COCOA_SYSTEM_HOTKEY_HELPER_MAC_H_