Proxy the PDF API to the PDF plugin.

This makes the Rotate Clockwise / Counterclockwise context menu items work.

Review URL: https://codereview.chromium.org/142413006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249366 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249366
Avoid using g_browser_process in extensions AppWindowAPI

This is a small step toward eliminating chrome/browser dependencies, which
we'll need in order to create app windows inside app_shell.

BUG=341251
TEST=browser_tests *WindowsApi*

Review URL: https://codereview.chromium.org/156283002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@249367 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 249367