Remove USE_SKIA define. It is no longer used anywhere.

No intended behavior change.

BUG=110881

Review URL: https://codereview.chromium.org/12939022

git-svn-id: http://src.chromium.org/svn/trunk/src/build@190744 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -1679,9 +1679,6 @@
         }],
       ],
     },
-    # TODO(teravest): Remove this define once uses of USE_SKIA are cleaned up
-    # throughout the codebase.
-    'defines' : ['USE_SKIA'],
     'conditions': [
       ['(OS=="mac" or OS=="ios") and asan==1', {
         'dependencies': [