[Tizen] Add MediaPlayer Implementation

This class is substitute for WebMediaPlayerImpl to be used in Tizen.
[Tizen] Add the RendererMediaPlayerManager

This class manages all the MediaPlayerImpl objects in the same
RenderView and also the IPC communication between MediaPlayerImpl
and BrowserMediaPlayerManager in the browser process.
[Tizen] IPC messages for Tizen media player

IPC Messages for notifying the media playback status between
renderer and browser processes.
[Tizen] Add BrowserMediaPlayerManager

This class manages all AudioSessionManager objects in the browser
process. It receives control operations from the render process, and
forwards them to corresponding AudioSessionManager object. Callbacks
from AudioSessionManager objects are converted to IPCs and then sent
to the render process.
[Tizen] Add Tizen Audio Session Manager integration

This class is for registering Audio Session Manager and
communicate media player callbacks with it.
[Tizen] Add audio-session-mgr to the list of crosswalk dependencies.
[Tizen] Chromium side changes needed for Tizen Audio Session Manager integration

This patch includes Chromium side changes needed for integrating
WebMediaPlayer with the Tizen audio session manager.
[Tizen] Add tizen-audio-session-manager patch to the Crosswalk spec file.
Merge pull request #817 from nagineni/policy_manager

[Tizen] Integrate WebMediaPlayer with Tizen Audio Session Manager