Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@271291 0039d316-1c4b-4281-b951-d872f2087c98

.DEPS.git

@@ -9,7 +9,7 @@ vars = {
     'git_url':
          'https://chromium.googlesource.com',
     'webkit_rev':
-         '@f59022a40f96f90379a3e27862a57598f9ab2e43',
+         '@3973deb9609cf7dcea7200aa5d93ba357fa69502',
     'angle_revision':
          '28bcf4ffeb49322fa019e2778c1fdd20f61d9ea6'
 }