Fix remote-to-local navigations in crashed subframes.

content/common/frame_messages.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // IPC messages for interacting with frames.
 // Multiply-included message file, hence no include guard.
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 645 matching lines @@
 IPC_MESSAGE_ROUTED1(FrameMsg_BeforeUnload, bool /* is_reload */)
 
 // Instructs the frame to swap out for a cross-site transition, including
 // running the unload event handler and creating a RenderFrameProxy with the
 // given |proxy_routing_id|. Expects a SwapOut_ACK message when finished.
 IPC_MESSAGE_ROUTED3(FrameMsg_SwapOut,
                     int /* proxy_routing_id */,
                     bool /* is_loading */,
                     content::FrameReplicationState /* replication_state */)
 
+// Requests that a provisional RenderFrame swaps itself into the frame tree,

[Charlie Reis, 2017/01/12 00:29:05]

nit: s/swaps/swap/

[alexmos, 2017/01/12 01:38:12]

Done.

+// replacing the RenderFrameProxy that it is associated with.  This is used
+// with remote-to-local frame navigations when the RenderFrameProxy corresponds
+// to a non-live (crashed) frame.  In that case, the browser process will send
+// this message as part of an early commit to stop showing the sad iframe
+// without waiting for the provisional RenderFrame's navigation to commit.
+IPC_MESSAGE_ROUTED0(FrameMsg_SwapIn)
+
 // Instructs the frame to stop the load in progress, if any.
 IPC_MESSAGE_ROUTED0(FrameMsg_Stop)
 
 // A message sent to RenderFrameProxy to indicate that its corresponding
 // RenderFrame has started loading a document.
 IPC_MESSAGE_ROUTED0(FrameMsg_DidStartLoading)
 
 // A message sent to RenderFrameProxy to indicate that its corresponding
 // RenderFrame has completed loading.
 IPC_MESSAGE_ROUTED0(FrameMsg_DidStopLoading)
@@ skipping 37 matching lines @@
 // doing so.
 IPC_MESSAGE_ROUTED1(FrameMsg_Reload,
                     bool /* bypass_cache */)
 
 // Notifies the color chooser client that the user selected a color.
 IPC_MESSAGE_ROUTED2(FrameMsg_DidChooseColorResponse, unsigned, SkColor)
 
 // Notifies the color chooser client that the color chooser has ended.
 IPC_MESSAGE_ROUTED1(FrameMsg_DidEndColorChooser, unsigned)
 
-// Notifies the corresponding RenderFrameProxy object to replace itself with the
-// RenderFrame object it is associated with.
+// Requests the corresponding RenderFrameProxy to be deleted and removed from
+// the frame tree.
 IPC_MESSAGE_ROUTED0(FrameMsg_DeleteProxy)
 
 // Request the text surrounding the selection with a |max_length|. The response
 // will be sent via FrameHostMsg_TextSurroundingSelectionResponse.
 IPC_MESSAGE_ROUTED1(FrameMsg_TextSurroundingSelectionRequest,
                     uint32_t /* max_length */)
 
 // Requests information about currently focused text input element from the
 // renderer.
 IPC_MESSAGE_ROUTED1(FrameMsg_FocusedFormFieldDataRequest, int /* request_id */)
@@ skipping 804 matching lines @@
 // nearest find result in the sending frame.
 IPC_MESSAGE_ROUTED2(FrameHostMsg_GetNearestFindResult_Reply,
                     int /* nfr_request_id */,
                     float /* distance */)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent FrameMsg, then ifdefs for platform specific FrameMsg, then
 // platform independent FrameHostMsg, then ifdefs for platform specific
 // FrameHostMsg.