Put back some scons files that the docs build parses, but rename them

with ".manifest", since we no longer have a scons build.

We should probably change the code that parses these to be simpler someday.
Review URL: http://codereview.chromium.org/341073

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@30774 0039d316-1c4b-4281-b951-d872f2087c98