mac: Swizzle out +[NSBundle mainBundle] for in process browser tests.

chrome/test/base/scoped_bundle_swizzler_mac.h

+// Copyright 2015 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_TEST_BASE_SCOPED_BUNDLE_SWIZZLER_MAC_H_
+#define CHROME_TEST_BASE_SCOPED_BUNDLE_SWIZZLER_MAC_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace base {
+namespace mac {
+class ScopedObjCClassSwizzler;
+}  // namespace mac
+}  // namespace base
+
+// Within a given scope, swizzles the implementation of +[NSBundle mainBundle]
+// to return a partial mock of the original bundle. This partial mock has a
+// custom bundle identifier.
+// Since this class swizzles a class method, it doesn't make sense to have more
+// than one instance of this class in existence at the same time.
+// The primary purpose of this class is to stub out the behavior of NSBundle for
+// AppKit, which makes assumptions about the functionality of +[NSBundle
+// mainBundle]. Code in Chrome should not require the use of this method, since
+// the NSBundle is always accessed through bundle_locations.h, and that NSBundle
+// can be directly stubbed.
+class ScopedBundleSwizzlerMac {
+ public:
+  ScopedBundleSwizzlerMac();
+  ~ScopedBundleSwizzlerMac();
+
+ private:
+  scoped_ptr<base::mac::ScopedObjCClassSwizzler> class_swizzler_;
+  DISALLOW_COPY_AND_ASSIGN(ScopedBundleSwizzlerMac);
+};
+
+#endif  // CHROME_TEST_BASE_SCOPED_BUNDLE_SWIZZLER_MAC_H_