MediaTimeProvider support fixes

Add MEDIA_SKIPPED event when resuming at a different time than
seeked to.

Send MEDIA_STARTED/PAUSED events only when playing (vs. when doing seek
previews)

Change-Id: I243ebf054303755ea8863229c3211694f2c204a7
Signed-off-by: Lajos Molnar <lajos@google.com>
Bug: 10954008
diff --git a/include/media/mediaplayer.h b/include/media/mediaplayer.h
index 2177c4c..4c05fc3 100644
--- a/include/media/mediaplayer.h
+++ b/include/media/mediaplayer.h
@@ -45,6 +45,7 @@
     MEDIA_STARTED           = 6,
     MEDIA_PAUSED            = 7,
     MEDIA_STOPPED           = 8,
+    MEDIA_SKIPPED           = 9,
     MEDIA_TIMED_TEXT        = 99,
     MEDIA_ERROR             = 100,
     MEDIA_INFO              = 200,