Fix race conditions in window snapshot code.

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 6811f77ec7ca84d728bd9bf969e66b7fa5166d75..3ee517b15fca111f510858cede26ee83dd61c4f4 100644
--- a/content/common/view_messages.h
+++ b/content/common/view_messages.h
@@ -805,6 +805,11 @@ 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 */)
+
 // 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
@@ -1861,10 +1866,6 @@ IPC_MESSAGE_ROUTED3(ViewHostMsg_WebUISend,
                     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.