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

chrome/test/base/scoped_bundle_swizzler_mac.mm

+// 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.
+
+#include "chrome/test/base/scoped_bundle_swizzler_mac.h"
+
+#import <Foundation/Foundation.h>
+
+#include "base/logging.h"
+#include "base/mac/foundation_util.h"
+#include "base/mac/scoped_objc_class_swizzler.h"
+#include "base/strings/sys_string_conversions.h"
+#import "third_party/ocmock/OCMock/OCMock.h"
+
+static NSBundle* g_original_main_bundle = nil;
+static id g_swizzled_main_bundle = nil;
+
+// A donor class that provides a +[NSBundle mainBundle] method that can be
+// swapped with NSBundle.
+@interface TestBundle : NSObject
++ (NSBundle*)mainBundle;
+@end
+
+@implementation TestBundle
++ (NSBundle*)mainBundle {
+  return g_swizzled_main_bundle;
+}
+@end
+
+ScopedBundleSwizzlerMac::ScopedBundleSwizzlerMac() {
+  CHECK(!g_swizzled_main_bundle);
+  CHECK(!g_original_main_bundle);
+
+  g_original_main_bundle = [NSBundle mainBundle];
+  g_swizzled_main_bundle =
+      [[OCMockObject partialMockForObject:g_original_main_bundle] retain];
+  NSString* identifier = base::SysUTF8ToNSString(base::mac::BaseBundleID());
+  CHECK(identifier);
+  [[[g_swizzled_main_bundle stub] andReturn:identifier] bundleIdentifier];
+
+  class_swizzler_.reset(new base::mac::ScopedObjCClassSwizzler(
+      [NSBundle class], [TestBundle class], @selector(mainBundle)));
+}
+
+ScopedBundleSwizzlerMac::~ScopedBundleSwizzlerMac() {
+  [g_swizzled_main_bundle release];
+  g_swizzled_main_bundle = nil;
+  g_original_main_bundle = nil;
+}