Update .DEPS.git

Cr-Commit-Position: refs/heads/master@{#288963}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288963 0039d316-1c4b-4281-b951-d872f2087c98

.DEPS.git

@@ -9,7 +9,7 @@ vars = {
     'git_url':
          'https://chromium.googlesource.com',
     'webkit_rev':
-         '@f449eff16af2f938f39672a4dd9997ae12b1e66f',
+         '@c9e7a2cdc9a246936c74ebbdeac26f6b57b0eb3e',
     'angle_revision':
          'bc75f36b04c8bab99bcecf8cdca16ecee3ac58ee'
 }