webkit/plugins/ppapi/*. This renamed the files and interface implementation
classes from foo.cc/Foo to ppb_foo_impl/PPB_Foo_Impl to match the proxy
ppb_foo_proxy/PPB_Foo_Proxy.

This moves plugin_switches.* from webkit/glue/plugins to webkit/plugins.
Review URL: http://codereview.chromium.org/5828003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@69424 0039d316-1c4b-4281-b951-d872f2087c98