Re-rebaseline flaky tests after auto-rebaseline tool picked the "wrong" rebaselines

TBR=ojan

Review URL: https://codereview.chromium.org/19917005

git-svn-id: svn://svn.chromium.org/blink/trunk@154841 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Have rebaseline-o-matic sync again after upload.

On long rebaselines, TestExpectations changes between the time the rebaseline
was started and the time it finished uploading. So, the dcommit is failing
with a conflict.

NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/19620004

git-svn-id: svn://svn.chromium.org/blink/trunk@154842 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Don't use Vector<UChar> to build strings

This CL removes a bunch of code sites that were using Vector<UChar> to
construct strings. That used to be a good way to construct strings, but in the
modern world, we have much better alternatives in the form of StringBuffer and
StringBuilder. (You should use StringBuffer if you know exactly how much memory
you need and you should use StringBuilder if you require a variable amount of
memory.)

This CL removes more clients of the StringImpl pointer. There are still a few
left, which require more study.

R=eseidel
BUG=262320
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/20002008

git-svn-id: svn://svn.chromium.org/blink/trunk@154843 bbb929c8-8fbe-4397-9dbb-9b2b20218538