Remove un-used variables in layer_tree_host_common

Thanks to vollick@ for actually finding these

Review URL: https://codereview.chromium.org/26574003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227734 0039d316-1c4b-4281-b951-d872f2087c98
Switching to a new format for sending errors.

BUG=164227
TEST=No

Review URL: https://codereview.chromium.org/24109007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227735 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227734
SVN changes up to revision 227735