Added SchemaMap::GetChanges().

This method allows comparing an older and a newer instance of SchemaMap and
get a list of components added and another of components removed.

BUG=108992
R=bartfab@chromium.org

Review URL: https://codereview.chromium.org/68933002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234516 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234516
Revert 234496 "Roll Skia DEPS to r12231"

> Roll Skia DEPS to r12231
> 
> R=rmistry@google.com
> 
> Review URL: https://codereview.chromium.org/69173004

TBR=robertphillips@google.com

Review URL: https://codereview.chromium.org/68203012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234517 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234518 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234517
SVN changes up to revision 234518