imported scss files from Github prototype project; 

BUG=330235

Review URL: https://codereview.chromium.org/113963003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244328 0039d316-1c4b-4281-b951-d872f2087c98
sync: Consistently refcount ModelSafeWorkers

Certain interfaces in sync had signatures that included vectors of raw
pointers to ModelSafeWorkers.  The use of raw pointers to refcounted
objects looks a lot like a bug waiting to happen.

This CL replaces any use of std::vector<ModelSafeWorker*> with
std::vector<scoped_refptr<ModelSafeWorker> >.  This is not expected to
alter sync behavior in any significant way.

BUG=332251

Review URL: https://codereview.chromium.org/130193002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244329 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244329
Have browser process shutdown metro viewer on Metro -> Metro restart.

Metro -> Metro restarts can happen as a result of changing about:flags, or a chrome update.  In order for the metro viewer to exit, it is necessary for the browser to notify the metro viewer that it needs to close itself.  This was happening for Metro -> Desktop restarts, but not for Metro -> Metro restarts.

BUG=332063

Review URL: https://codereview.chromium.org/130223002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244330 0039d316-1c4b-4281-b951-d872f2087c98
Enable unwind support with buildtype=Official branding=Chrome in Debug mode

The previous patch removed unwind support on x64 official builds,
including Debug builds. That may have been a bit too far. Add it back to
Debug builds (but not Release builds).

BUG=180975

Review URL: https://codereview.chromium.org/131193005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244331 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244331