Hook up the PPB_Flash_Print interface to new host system.

ppapi/host/instance_message_filter.h

Index: ppapi/host/instance_message_filter.h
diff --git a/ppapi/host/instance_message_filter.h b/ppapi/host/instance_message_filter.h
new file mode 100644
index 0000000000000000000000000000000000000000..2392b6c65328a9ae8e0be861cad3cbea3c698a18
--- /dev/null
+++ b/ppapi/host/instance_message_filter.h
@@ -0,0 +1,54 @@
+// 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.
+
+#ifndef PPAPI_HOST_INSTANCE_MESSAGE_FILTER_H_
+#define PPAPI_HOST_INSTANCE_MESSAGE_FILTER_H_
+
+#include "base/basictypes.h"
+#include "ppapi/host/ppapi_host_export.h"
+
+namespace IPC {
+class Message;
+}
+
+namespace ppapi {
+namespace host {
+
+class PpapiHost;
+
+class PPAPI_HOST_EXPORT InstanceMessageFilter {
+ public:
+  // Invoked when the PpapiHost is being destroyed. Gives subclasses a chance
+  // to cleanup. At the time this is invoked, host() returns NULL. It is safe
+  // to |delete this| from this function.
+  virtual void PpapiHostDestroyed(PpapiHost* host) {}
+
+  // Processes an instance message from the plugin process. Returns true if the
+  // message was handled. On false, the PpapiHost will forward the message to
+  // the next filter.
+  virtual bool OnInstanceMessageReceived(const IPC::Message& msg) = 0;
+
+  // Will return NULL if the host is destroyed.
+  PpapiHost* host() { return host_; }
+
+ protected:
+  explicit InstanceMessageFilter(PpapiHost* host);
+  virtual ~InstanceMessageFilter();
+
+ private:
+  friend class PpapiHost;
+
+  // Invoked by PpapiHost when the host is destroyed. Nulls out host_ and calls
+  // PpapiHostDestroyed().
+  void CallPpapiHostDestroyed();

[dmichael (off chromium), 2012/07/25 16:57:27]

nit: Since it does a little more than call PpapiHostDestroyed, maybe should be
PpapiHostWasDestroyed()?

+
+  PpapiHost* host_;
+
+  DISALLOW_COPY_AND_ASSIGN(InstanceMessageFilter);
+};
+
+}  // namespace host
+}  // namespace ppapi
+
+#endif  // PPAPI_HOST_INSTANCE_MESSAGE_FILTER_H_