[Mac] Maximise timer slack for background tabs

content/public/browser/web_contents_user_data.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 CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_USER_DATA_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_USER_DATA_H_
 
 #include "base/logging.h"
 #include "base/supports_user_data.h"
 #include "content/public/browser/web_contents.h"
 
 namespace content {
 
 // A base class for classes attached to, and scoped to, the lifetime of a
 // WebContents. For example:
 //
 // --- in foo_tab_helper.h ---
 // class FooTabHelper : public content::WebContentsUserData<FooTabHelper> {
 //  public:
 //   virtual ~FooTabHelper();
 //   // ... more public stuff here ...
 //  private:
 //   explicit FooTabHelper(content::WebContents* contents);
 //   friend class content::WebContentsUserData<FooTabHelper>;
 //   // ... more private stuff here ...
-// }
+// };

[Avi (use Gerrit), 2014/05/20 14:41:39]

This is correct but doesn't belong in this CL.

 // --- in foo_tab_helper.cc ---
 // DEFINE_WEB_CONTENTS_USER_DATA_KEY(FooTabHelper);
 //
 template <typename T>
 class WebContentsUserData : public base::SupportsUserData::Data {
  public:
   // Creates an object of type T, and attaches it to the specified WebContents.
   // If an instance is already attached, does nothing.
   static void CreateForWebContents(WebContents* contents) {
     DCHECK(contents);
@@ skipping 31 matching lines @@
 // a declaration. Without it, this would be merely a declaration of a template
 // specialization. (C++98: 14.7.3.15; C++11: 14.7.3.13)
 //
 #define DEFINE_WEB_CONTENTS_USER_DATA_KEY(TYPE) \
 template<>                                      \
 int content::WebContentsUserData<TYPE>::kLocatorKey = 0
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_USER_DATA_H_