Updating trunk VERSION from 1876.0 to 1877.0

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255517 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255517
force constrained signed flow in avatar bubble on mac

BUG=341634

Review URL: https://codereview.chromium.org/188753003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@255519 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 255519