Implement screen orientation for out-of-process iframes.

content/common/page_messages.h

Index: content/common/page_messages.h
diff --git a/content/common/page_messages.h b/content/common/page_messages.h
index 6d81f3f965eaff01abb2f49c8d88bd3b60ac1378..4fa9f056c3b47307c92e7cb811f6378575e722f9 100644
--- a/content/common/page_messages.h
+++ b/content/common/page_messages.h
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "content/common/page_message_enums.h"
+#include "content/public/common/screen_info.h"
 #include "ipc/ipc_message_macros.h"
 #include "ui/gfx/geometry/rect.h"
 
@@ -45,6 +46,10 @@ IPC_MESSAGE_ROUTED2(PageMsg_SetHistoryOffsetAndLength,
 
 IPC_MESSAGE_ROUTED1(PageMsg_AudioStateChanged, bool /* is_audio_playing */)
 
+// Sent to OOPIF renderers when the main frame's ScreenInfo changes.
+IPC_MESSAGE_ROUTED1(PageMsg_UpdateScreenInfo,
+                    content::ScreenInfo /* screen_info */)
+
 // -----------------------------------------------------------------------------
 // Messages sent from the renderer to the browser.