Revert 230981 "Make TRANSPARENT windows be layered windows on wi..."

> Make TRANSPARENT windows be layered windows on win aura
> 
> This builds on jbauman's patch to plumb use_software_compositor
> from here: https://codereview.chromium.org/23621054/
> 
> The motivation here is that we currently have very different
> event, focus, activation paths on DWM vs. classic because of the
> differences between when we use top-level windows and when we
> don't. With this change, all translucent (i.e. shaped) windows
> are converted to being top level (always), and are rendered by
> the software compositor and are converted to layered windows for
> rendering.
> 
> BUG=293218 and many other focus/activation bugs
> 
> Review URL: https://codereview.chromium.org/26888006

BUG=312277,313349,313462
TBR=scottmg@chromium.org,cpu@chromium.org,ananta@chromium.org

Review URL: https://codereview.chromium.org/56623002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232511 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232511