Fixed a variable that may be used uninitialized.
Prevents a warning with GCC 4.8 on Android.

BUG=

Review URL: https://codereview.chromium.org/221873006

git-svn-id: svn://svn.chromium.org/blink/trunk@170675 bbb929c8-8fbe-4397-9dbb-9b2b20218538