Use a direct include of strings headers in ppapi/, printing/.

BUG=247723
TEST=none
[email protected]

Review URL: https://chromiumcodereview.appspot.com/16366009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@205664 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/printing/print_settings.h b/printing/print_settings.h
index 3a55502..5728bf7 100644
--- a/printing/print_settings.h
+++ b/printing/print_settings.h
@@ -7,7 +7,7 @@
 
 #include <string>
 
-#include "base/string16.h"
+#include "base/strings/string16.h"
 #include "printing/page_range.h"
 #include "printing/page_setup.h"
 #include "printing/print_job_constants.h"