Fix race conditions in window snapshot code.

content/common/view_messages.h

 // Copyright (c) 2012 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 page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include "base/memory/shared_memory.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
@@ skipping 788 matching lines @@
 // page_ids >= |minimum_page_id| in the new tab are appended to the history.
 //
 // For example, suppose the history of page_ids in the new tab's RenderView
 // is [4 7 8]. This is merged into an existing tab with 3 history items, and
 // all pages in the new tab with page_id >= 7 are to be preserved.
 // The resulting page history is [-1 -1 -1 7 8].
 IPC_MESSAGE_ROUTED2(ViewMsg_SetHistoryLengthAndPrune,
                     int, /* merge_history_length */
                     int32 /* minimum_page_id */)
 
+// Tells the renderer the browser's notion of its process ID.
+// Some subsystems, like LatencyInfo, require this to be known to the renderer.
+IPC_MESSAGE_CONTROL1(ViewMsg_SetRendererProcessID,
+                     int64 /* process_id */)

[jln (very slow on Chromium), 2013/10/07 18:25:42]

Please, use base::ProcessId

+
 // Tells the renderer to create a new view.
 // This message is slightly different, the view it takes (via
 // ViewMsg_New_Params) is the view to create, the message itself is sent as a
 // non-view control message.
 IPC_MESSAGE_CONTROL1(ViewMsg_New,
                      ViewMsg_New_Params)
 
 // Reply in response to ViewHostMsg_ShowView or ViewHostMsg_ShowWidget.
 // similar to the new command, but used when the renderer created a view
 // first, and we need to update it.
@@ skipping 1035 matching lines @@
 IPC_MESSAGE_ROUTED1(ViewHostMsg_HasTouchEventHandlers,
                     bool /* has_handlers */)
 
 // A message from HTML-based UI.  When (trusted) Javascript calls
 // send(message, args), this message is sent to the browser.
 IPC_MESSAGE_ROUTED3(ViewHostMsg_WebUISend,
                     GURL /* source_url */,
                     std::string  /* message */,
                     base::ListValue /* args */)
 
-// Requests a snapshot of the given window.
-IPC_MESSAGE_ROUTED1(ViewHostMsg_GetWindowSnapshot,
-                    int /* snapshot_id */)
-
 // A renderer sends this to the browser process when it wants to create a ppapi
 // plugin.  The browser will create the plugin process if necessary, and will
 // return a handle to the channel on success.
 //
 // The plugin_child_id is the ChildProcessHost ID assigned in the browser
 // process. This ID is valid only in the context of the browser process and is
 // used to identify the proper process when the renderer notifies it that the
 // plugin is hung.
 //
 // On error an empty string and null handles are returned.
@@ skipping 500 matching lines @@
 // synchronously (see crbug.com/120597). This IPC message sends the character
 // bounds after every composition change to always have correct bound info.
 IPC_MESSAGE_ROUTED2(ViewHostMsg_ImeCompositionRangeChanged,
                     gfx::Range /* composition range */,
                     std::vector<gfx::Rect> /* character bounds */)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent ViewMsg, then ifdefs for platform specific ViewMsg, then platform
 // independent ViewHostMsg, then ifdefs for platform specific ViewHostMsg.