Add a .clang-format file to Blink.
Add a .clang-format file to Blink.

This way, a recent clang-format will use the correct style without that the
user has to pass an explicit -style parameter.

BUG=none
NOTRY=true

Review URL: https://codereview.chromium.org/23503027

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@165335 bbb929c8-8fbe-4397-9dbb-9b2b20218538

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk