Implement getters for app window bounds API

This is the first patch for the new app window bounds API.
- The current Bounds class was renamed ContentBounds in order to 
introduce a different Bounds class for the new API
- The properties of the innerBounds and outerBounds can now be read
- Some already deprecated bounds fields in CreateWindowOptions are no
longer documented

BUG=315471

Review URL: https://codereview.chromium.org/179393002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253729 0039d316-1c4b-4281-b951-d872f2087c98
Send software frame ack even when compositor doesn't exist.

Otherwise the renderer would never create more frames.

BUG=335967

Review URL: https://codereview.chromium.org/177243015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253730 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253729
SVN changes up to revision 253730