Create Mojo service for locking/unlocking screen orientation.

content/browser/screen_orientation/screen_orientation_context.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_SCREEN_ORIENTATION_SCREEN_ORIENTATION_CONTEXT_H_
+#define CONTENT_BROWSER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_CONTEXT_H_
+
+#include "base/observer_list.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+// Provides information about changes within a screen orientation context to a
+// set of observers of that context.
+class CONTENT_EXPORT ScreenOrientationContext {
+ public:
+  class Observer {
+   public:
+    // Called when the screen orientation changes.
+    virtual void OnScreenOrientationChange() = 0;
+
+    // Called when a new lock request is received within this screen
+    // orientation context.
+    virtual void OnNewLockRequest() = 0;
+
+   protected:
+    virtual ~Observer() {}
+  };
+
+  ScreenOrientationContext();
+  virtual ~ScreenOrientationContext();
+
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+
+  // Notifies observers that screen orientation changed.
+  void OnScreenOrientationChange();
+
+  // Notifies observers that a new lock request was received.
+  void OnNewLockRequest();
+
+ private:
+  ObserverList<Observer, true> observer_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScreenOrientationContext);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_SCREEN_ORIENTATION_SCREEN_ORIENTATION_CONTEXT_H_