Create a new RenderFrameHost per child frame when --site-per-process is enabled.

content/common/view_messages.h

Index: content/common/view_messages.h
diff --git a/content/common/view_messages.h b/content/common/view_messages.h
index 04d5c098d0822bec5e87499b511eea4701c1b53a..2a6aa9ad4fa54b7f95756b430cc29bc832cf2e70 100644
--- a/content/common/view_messages.h
+++ b/content/common/view_messages.h
@@ -2249,19 +2249,6 @@ IPC_MESSAGE_CONTROL3(ViewHostMsg_DidLose3DContext,
                      content::ThreeDAPIType /* context_type */,
                      int /* arb_robustness_status_code */)
 
-// This message is sent when a frame is added to the DOM.
-IPC_MESSAGE_ROUTED3(ViewHostMsg_FrameAttached,
-                    int64 /* parent_frame_id*/,
-                    int64 /* frame_id */,
-                    std::string /* frame_name */)
-
-// Notifies the browser that the frame with the given id was detached. The
-// |parent_frame_id| is -1 for the top level frame, otherwise the id of the
-// immediate parent of the detached frame.
-IPC_MESSAGE_ROUTED2(ViewHostMsg_FrameDetached,
-                    int64 /* parent_frame_id */,
-                    int64 /* frame_id */)
-
 // Notifies the browser that document has parsed the body. This is used by the
 // ResourceScheduler as an indication that bandwidth contention won't block
 // first paint.