Revert 240112 "Revert of https://codereview.chromium.org/104333002/"

Tests failed on Linux Aura

> Revert of https://codereview.chromium.org/104333002/
> Reason for revert: Hopefully cl 100393008 should improve things on Windows
> 
> Review URL: https://codereview.chromium.org/104653002

TBR=mlamouri@chromium.org

Review URL: https://codereview.chromium.org/99093008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240124 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 240124
WebMediaPlayerImpl: RenderViewObserver instead of MessageLoop::DestructionObserver.

RenderThreadImpl is torn down before the main thread's MessageLoop is, and some
of WebMediaPlayerImpl's dependencies require the render thread to still be
alive, so move its tear-down to earlier in the process.

BUG=304967

Review URL: https://codereview.chromium.org/112173002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240125 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 240125