added prevent check for m_player in duration()

added prevent check for m_player in duration()

BUG=395076
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=178512

[Srirama, 2014-07-18 16:48:24]

Added preventive check for m_player in duration() to avoid the crash. As
reported in the issue there is a case where m_player is cleared but m_readyState
is not reset to HAVE_NOTHING. From initial analysis it looks to me that issue is
in userCancelledLoad().
clearMediaPlayer(-1); is getting called at the beginning and there is a chance
of returning from next statement in which case m_readyState will not be reset to
HAVE_NOTHING.
if (m_networkState == NETWORK_EMPTY || m_completelyLoaded)
    return;
Adding this preventive check till the actual issue is fixed.
PTAL

[philipj_slow, 2014-07-18 22:31:27]

lgtm

[Srirama, 2014-07-19 03:27:52]

The CQ bit was checked by srirama.m@samsung.com

[commit-bot: I haz the power, 2014-07-19 03:28:53]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/srirama.m@samsung.com/407523002/1

[commit-bot: I haz the power, 2014-07-19 03:31:21]

Change committed as 178512