dashplayer: Send buffering start event conditionally

Send buffering start event to application only if
video decoder is instantiated.

Change-Id: I99465b45b2f68efbd40eada3d03a235bb6694223
mm-video: vdec: Set input buffer size dynamically

OMX client can request the input buffer size based
on frame resolution. This change supports overriding
default input buffer size if the value requested by
client is greater than default input buffer size.

Change-Id: I376d60319acb462b4f806217ec57ad19ddee357b
Merge "dashplayer: Send buffering start event conditionally"
Merge "mm-video: vdec: Set input buffer size dynamically"
Merge remote-tracking branch 'ca/kk_2.7_rb1.15' into kk-4.4