Rename MinimalShell to WMTestHelper.

As requested by Ben in https://codereview.chromium.org/74183002/

* Rename minimal_shell.* to wm_test_helper.*

BUG=308710
TEST=None
R=ben@chromium.org

Review URL: https://codereview.chromium.org/70513007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235580 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235580
Add SetOffset to PPB_Graphics2D_Dev

Add a SetOffset function to PPB_Graphics2D_Dev which allows the graphics context to be offset into the plugin element. This allows having a graphics context which is smaller than the plugin element and painting into only a portion of the plugin elements. This makes it possible to do viewporting for very large plugins.

R=piman@chromium.org, tsepez@chromium.org, yzshen@chromium.org

Review URL: https://codereview.chromium.org/25661002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235581 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235581