Reland 1: "mac: Allow Chrome to hand off its active URL to other devices."

chrome/browser/ui/cocoa/handoff_active_url_observer_bridge.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 CHROME_BROWSER_UI_COCOA_HANDOFF_ACTIVE_URL_OBSERVER_BRIDGE_H_
+#define CHROME_BROWSER_UI_COCOA_HANDOFF_ACTIVE_URL_OBSERVER_BRIDGE_H_
+
+#import <Cocoa/Cocoa.h>
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/ui/cocoa/handoff_active_url_observer_delegate.h"
+
+namespace content {
+class WebContents;
+}
+
+class HandoffActiveURLObserver;
+
+// A protocol that allows ObjC objects to receive delegate callbacks from
+// HandoffActiveURLObserver.
+@protocol HandoffActiveURLObserverBridgeDelegate
+- (void)handoffActiveURLChanged:(content::WebContents*)webContents;
+@end
+
+// This class allows an ObjC object to receive the delegate callbacks from an
+// HandoffActiveURLObserver.
+class HandoffActiveURLObserverBridge : public HandoffActiveURLObserverDelegate {
+ public:
+  explicit HandoffActiveURLObserverBridge(
+      NSObject<HandoffActiveURLObserverBridgeDelegate>* delegate);
+
+  ~HandoffActiveURLObserverBridge() override;
+
+ private:
+  void HandoffActiveURLChanged(content::WebContents* web_contents) override;
+
+  // Instances of this class should be owned by their |delegate_|.
+  NSObject<HandoffActiveURLObserverBridgeDelegate>* delegate_;
+
+  // The C++ object that this class acts as a bridge for.
+  scoped_ptr<HandoffActiveURLObserver> observer_;
+
+  DISALLOW_COPY_AND_ASSIGN(HandoffActiveURLObserverBridge);
+};
+
+#endif  // CHROME_BROWSER_UI_COCOA_HANDOFF_ACTIVE_URL_OBSERVER_BRIDGE_H_