Remove duplicated headers from modules/ directory where the implementation file includes the same dependencies as the corresponding primary header. 

Remove the dependencies from headers where possible.

BUG=317231

Review URL: https://codereview.chromium.org/99733006

git-svn-id: svn://svn.chromium.org/blink/trunk@163907 bbb929c8-8fbe-4397-9dbb-9b2b20218538