Delay creation of BrowserPluginMsg_X messages until after attach.

content/browser/browser_plugin/browser_plugin_guest.h

Index: content/browser/browser_plugin/browser_plugin_guest.h
diff --git a/content/browser/browser_plugin/browser_plugin_guest.h b/content/browser/browser_plugin/browser_plugin_guest.h
index f302c6d9d094de9462f4fe3bf2b4b534841ff3e6..3dcaaeedbb7b8bb1f35f5fdf86c316b1d873eab8 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.h
+++ b/content/browser/browser_plugin/browser_plugin_guest.h
@@ -18,6 +18,7 @@
 #ifndef CONTENT_BROWSER_BROWSER_PLUGIN_BROWSER_PLUGIN_GUEST_H_
 #define CONTENT_BROWSER_BROWSER_PLUGIN_BROWSER_PLUGIN_GUEST_H_
 
+#include <functional>
 #include <map>
 #include <queue>
 
@@ -70,6 +71,9 @@ class RenderWidgetHostViewBase;
 class SiteInstance;
 struct DropData;
 
+typedef std::function<IPC::Message*(int browser_plugin_id)>

[lazyboy, 2015/10/16 00:15:48]

Guess the mac bots didn't like it. Lucas and I couldn't find any instance of
std::function in chrome/content/blink.

+    BrowserPluginMessageFunc;
+
 // A browser plugin guest provides functionality for WebContents to operate in
 // the guest role and implements guest-specific overrides for ViewHostMsg_*
 // messages.
@@ -202,6 +206,7 @@ class CONTENT_EXPORT BrowserPluginGuest : public GuestHost,
   // Helper to send messages to embedder. If this guest is not yet attached,
   // then IPCs will be queued until attachment.
   void SendMessageToEmbedder(IPC::Message* msg);
+  void SendMessageToEmbedder(BrowserPluginMessageFunc msg_func);
 
   // Returns whether the guest is attached to an embedder.
   bool attached() const { return attached_; }
@@ -460,6 +465,7 @@ class CONTENT_EXPORT BrowserPluginGuest : public GuestHost,
   // This is a queue of messages that are destined to be sent to the embedder
   // once the guest is attached to a particular embedder.
   std::deque<linked_ptr<IPC::Message> > pending_messages_;
+  std::deque<BrowserPluginMessageFunc> pending_message_funcs_;
 
   BrowserPluginGuestDelegate* const delegate_;