cc: Ensure changes to a Layer's content bounds or scale get pushed

This changes UpdateLayerContentsScale(Layer* layer, ...) so that if
the layer's content bounds or contents scale are changed, then its
needs_push_properties() flag is set.

BUG=345267

Review URL: https://codereview.chromium.org/178303002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253140 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253140