Move message handlers that don't belong in RenderProcessHostImpl to their own files.

content/browser/renderer_host/mhtml_generation_message_filter.cc

Index: content/browser/renderer_host/mhtml_generation_message_filter.cc
diff --git a/content/browser/renderer_host/mhtml_generation_message_filter.cc b/content/browser/renderer_host/mhtml_generation_message_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..64029e9ad517de96721f206bb51cde5bd083f814
--- /dev/null
+++ b/content/browser/renderer_host/mhtml_generation_message_filter.cc
@@ -0,0 +1,38 @@
+// 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.
+
+#include "content/browser/renderer_host/mhtml_generation_message_filter.h"
+
+#include "content/browser/download/mhtml_generation_manager.h"
+#include "content/common/view_messages.h"
+
+using content::BrowserMessageFilter;
+
+namespace content {
+
+MHTMLGenerationMessageFilter::MHTMLGenerationMessageFilter() {
+}
+
+MHTMLGenerationMessageFilter::~MHTMLGenerationMessageFilter() {
+}
+
+bool MHTMLGenerationMessageFilter::OnMessageReceived(
+    const IPC::Message& message,
+    bool* message_was_ok) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(MHTMLGenerationMessageFilter,
+                           message,
+                           *message_was_ok)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_SavedPageAsMHTML, OnSavedPageAsMHTML)

[jam, 2012/05/02 18:15:00]

a new filter just for one message? that seems a bit excessive. i'd be hesitant
if new messages get one filter each.

+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP_EX()
+  return handled;
+}
+
+void MHTMLGenerationMessageFilter::OnSavedPageAsMHTML(int job_id,
+                                                      int64 data_size) {
+  MHTMLGenerationManager::GetInstance()->MHTMLGenerated(job_id, data_size);
+}
+
+} // namespace content