Keep event page alive when there's some Pepper plugin on it.

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 1247 matching lines @@
                     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 */)
 
 #if defined(ENABLE_PLUGINS)
+// Notification sent from a renderer to the browser that a Pepper plugin
+// instance is attached to the page DOM.
+IPC_MESSAGE_ROUTED0(ViewHostMsg_PepperInstanceCreated)

[nasko, 2015/05/11 16:24:08]

Please don't add any more IPCs for RenderView. It is a deprecated object and
shouldn't be getting new functionality.

[emaxx, 2015/05/18 15:06:29]

Done.

+
+// Notification sent from a renderer to the browser that a Pepper plugin
+// instance is removed from the page DOM.
+IPC_MESSAGE_ROUTED0(ViewHostMsg_PepperInstanceDeleted)
+
 // 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 353 matching lines @@
 // cached by the OS. Please see RenderMessageFilter::OnPreCacheFontCharacters
 // for details.
 IPC_SYNC_MESSAGE_CONTROL2_0(ViewHostMsg_PreCacheFontCharacters,
                             LOGFONT /* font_data */,
                             base::string16 /* characters */)
 #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.