Make ContentVideoView accept application contexts.

Make ContentVideoView accept application contexts.

This is needed for the WebView, as some apps instantiate it
with an application context.

We also improve the detection of activity contexts.

BUG=428952
Committed: https://crrev.com/0e726250f02bd44636a1cc3a4660dd90d30d3a64
Cr-Commit-Position: refs/heads/master@{#302264}

[Ignacio Solla, 2014-10-30 20:06:46]

igsolla@chromium.org changed reviewers:
+ benm@chromium.org

[Ignacio Solla, 2014-10-30 20:07:40]

igsolla@chromium.org changed reviewers:
+ michaelbai@chromium.org

[michaelbai, 2014-10-30 20:51:45]

I assumed you fully test it in WebView, if so LGTM

[Ignacio Solla, 2014-10-31 09:48:05]

On 2014/10/30 20:51:45, michaelbai wrote:
> I assumed you fully test it in WebView, if so LGTM

Yes, I tested this in the WebView and fullscreen video works with an application
context. 

The only thing that I could find that requires an activity context is the
AlertDialog. Hopefully I haven't missed anything. Can you still remember why the
old implementation needed it?

[benm (inactive), 2014-10-31 13:42:13]

lgtm

[Ignacio Solla, 2014-10-31 13:46:54]

The CQ bit was checked by igsolla@chromium.org

[commit-bot: I haz the power, 2014-10-31 13:47:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/682223006/1

[commit-bot: I haz the power, 2014-10-31 14:37:22]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-31 14:37:51]

Patchset 1 (id:??) landed as
https://crrev.com/0e726250f02bd44636a1cc3a4660dd90d30d3a64
Cr-Commit-Position: refs/heads/master@{#302264}