Support sending a sliced file in chromium.

BUG=none
TEST=The WebKit Layout test.

Review URL: http://codereview.chromium.org/594036

git-svn-id: http://src.chromium.org/svn/trunk/src/build@42559 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

features_override.gypi

@@ -11,6 +11,7 @@
     # but not listed below, it will revert to its hardcoded webkit value.
     'feature_defines': [
       'ENABLE_3D_CANVAS=1',
+      'ENABLE_BLOB_SLICE=1',
       'ENABLE_CHANNEL_MESSAGING=1',
       'ENABLE_DATABASE=1',
       'ENABLE_DATAGRID=0',