Print only the focused frame.  This makes more sense than trying to print all frames since most of the time you end up with ugly clipping and scroll bars on the printed page.
This also fixes printing issue with print selection since we don't pick up the currently selected text if's not in the main frame.
Also did some refactoring of the printing test in render_view_unittest.  Mainly to reuse the new Image class.

BUG=http://crbug.com/15250
TEST=Print pages with frames.  Print selection when using multiple frames (one example in bug).

Review URL: http://codereview.chromium.org/149644

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20876 0039d316-1c4b-4281-b951-d872f2087c98

• chrome/chrome.gyp[diff]
• chrome/renderer/mock_printer.cc[diff]
• chrome/renderer/mock_printer.h[diff]
• chrome/renderer/mock_printer_driver_win.cc[Deleted - diff]
• chrome/renderer/mock_printer_driver_win.h[Deleted - diff]
• chrome/renderer/render_view.cc[diff]
• chrome/renderer/render_view.h[diff]
• chrome/renderer/render_view_unittest.cc[diff]
• printing/image.cc[diff]
• printing/image.h[diff]