Separate RendererCdmManager from RendererMediaPlayerManager.

Separate RendererCdmManager from RendererMediaPlayerManager.

This CL also updates the prefixed EME implementation on Android to use the new
RendererCdmManager. In a follow up CL RendererCdmManager will also be used by
the unprefixed EME implementation.

BUG=338910
TEST=Test page still works.

[xhwang, 2014-05-08 01:00:45]

PTAL

CLs to follow:
1, Support WD EME using the new RendererCdmManager.
2, Move CDM IPC path out of Android so it can be shared by multiple platforms.

[xhwang, 2014-05-08 01:03:24]

PS 1 copies RendererMediaPlayerManager.* to RendererCdmPlayerManager.* so that I
have a good base to show the diff. Please review the diff between PS1 and PS2.

[xhwang, 2014-05-08 16:44:47]

I think I need to make more changes in this CL. Please hold off reviewing this
CL. Thanks!

More details:
The render frames can be from different proceses (crazy!), so routing IDs cannot
be used to uniquely identify RenderFrames. Also, I should use
RenderFrameHost::Send() instead of WebContentsObserver::Send() to send IPCs back
to RenderFrameObservers.

[xhwang, 2014-05-08 21:37:26]

It seems pretty hard to have a cleaner solution than the current one without
changing RendererMediaPlayerManager to use RenderFrameObserver. So I'd like to
keep this CL as is, and I'll clean them up in the next CL.

PTAL

[xhwang, 2014-05-23 22:10:21]

On 2014/05/08 21:37:26, xhwang wrote:
> It seems pretty hard to have a cleaner solution than the current one without
> changing RendererMediaPlayerManager to use RenderFrameObserver. So I'd like to
> keep this CL as is, and I'll clean them up in the next CL.
> 
> PTAL

This CL is obsolete now. It's replaced by
https://codereview.chromium.org/295103015/