GitLab

This contains fixes for the following sorts of issues:
* Signedness mismatch
* Possibly-uninitialized local variable
* Assignment inside conditional
* Nonstandard extension: unnamed struct/union

This also contains a very small number of other cleanups/simplifications to
nearby code.

BUG=81439
TEST=none

Review URL: https://codereview.chromium.org/377723002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@283161 0039d316-1c4b-4281-b951-d872f2087c98