OOPIF: Handle cross-site frames being blocked by X-Frame-Options or CSP.

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 b990cdb6c8ad08169870c8ce5dded0f811622d52..337f92c0948f03f56a753482bfcd2e4686108dcc 100644
--- a/content/common/frame_messages.h
+++ b/content/common/frame_messages.h
@@ -846,6 +846,13 @@ IPC_MESSAGE_ROUTED1(FrameMsg_SerializeAsMHTML, FrameMsg_SerializeAsMHTML_Params)
 IPC_MESSAGE_ROUTED1(FrameMsg_SetFrameOwnerProperties,
                     blink::WebFrameOwnerProperties /* frame_owner_properties */)
 
+// Notifies the frame that its load was blocked while loading.  This is
+// currently used by X-Frame-Options or CSP frame-ancestors.  The frame uses
+// this to perform some special processing (setting its origin to unique,
+// dispatching a load event on the frame's owner) so that one can't tell
+// whether this load was blocked or not.
+IPC_MESSAGE_ROUTED0(FrameMsg_BlockedLoad)
+
 // Request to continue running the sequential focus navigation algorithm in
 // this frame.  |source_routing_id| identifies the frame that issued this
 // request.  This message is sent when pressing <tab> or <shift-tab> needs to
@@ -995,6 +1002,13 @@ IPC_MESSAGE_ROUTED2(FrameHostMsg_DidChangeFrameOwnerProperties,
                     int32_t /* subframe_routing_id */,
                     blink::WebFrameOwnerProperties /* frame_owner_properties */)
 
+// Notifies the browser process that a subframe was blocked by
+// X-Frame-Options or CSP frame-ancestors while loading.
+//
+// TODO(mkwst, alexmos): This will become unnecessary once X-Frame-Options and
+// CSP enforcement moves to the browser process (https://crbug.com/555418).
+IPC_MESSAGE_ROUTED0(FrameHostMsg_BlockedLoad)
+
 // Changes the title for the page in the UI when the page is navigated or the
 // title changes. Sent for top-level frames.
 IPC_MESSAGE_ROUTED2(FrameHostMsg_UpdateTitle,