Make PageScaleFactor work for oopif subframes.

content/common/frame_messages.h

Index: content/common/frame_messages.h
diff --git a/content/common/frame_messages.h b/content/common/frame_messages.h
index 90923442602cc1558cfafd0d49cc9ae7fc831d99..e70be71e0d523c438e0d2186556abc2ed34e5598 100644
--- a/content/common/frame_messages.h
+++ b/content/common/frame_messages.h
@@ -942,6 +942,14 @@ IPC_MESSAGE_ROUTED0(FrameMsg_SetHasReceivedUserGesture)
 IPC_MESSAGE_ROUTED1(FrameMsg_RunFileChooserResponse,
                     std::vector<content::FileChooserFileInfo>)
 
+// Used by the main-frame renderer to propagate page scale to subframes in other
+// renderer processes.
+IPC_MESSAGE_ROUTED1(FrameHostMsg_RestorePageScaleFactorOnLoad,
+                    float /* page_scale */)
+
+IPC_MESSAGE_ROUTED1(FrameMsg_SetPageScaleFactor,
+                    double /* page_scale_factor */)
+
 // -----------------------------------------------------------------------------
 // Messages sent from the renderer to the browser.