Audio continue to played even if paused manually

Currently, audio will resume playing after a phone call
or notification even if the user had manually paused playback.

This patch addresses that by introducing a new player state
to distinguish the user pausing playback and the browser
losing audio focus for some other reason. Audio will only
 resume if the browser temporarily lost audio focus and
not when the user has manually paused playback.

Change-Id: I9e8beaedb0fcc5afe920068297ed9c387eab2ac8
Signed-off-by: Roger Chen <cxr514033970@gmail.com>
FIX Null Pointer Exception on dialog cancel

Null Pointer Exception occurs because mWebViewCore instance
is made to null while calling destroyJava(). When
1.webview hosting activity goest to background, without calling webview onPause().
2. If app is launched again (having launchmode:singletask ) and another activity (not  webview hosting) comes on top top.
3. It destorys the previous activity holding webview which internally tries to cancel the dialog, but webviewcore instance is null.
Null pointer exception is raised.

Change-Id: Idbcd30d0b0d4a35819444bbaa5c73cced8bb35a3
Signed-off-by: Amit Kumar <amitkecian@gmail.com>