Don't make classes derive from ChildProcessHost, and instead have them use it through composition...

content/browser/ppapi_plugin_process_host.cc

 // Copyright (c) 2011 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/ppapi_plugin_process_host.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/process_util.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/plugin_service.h"
 #include "content/browser/renderer_host/render_message_filter.h"
+#include "content/common/child_process_host.h"
 #include "content/common/child_process_messages.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/pepper_plugin_info.h"
 #include "content/public/common/process_type.h"
 #include "ipc/ipc_switches.h"
 #include "net/base/network_change_notifier.h"
 #include "ppapi/proxy/ppapi_messages.h"
 
 class PpapiPluginProcessHost::PluginNetworkObserver
     : public net::NetworkChangeNotifier::IPAddressObserver,
@@ skipping 53 matching lines @@
   PpapiPluginProcessHost* plugin_host =
       new PpapiPluginProcessHost();
   if(plugin_host->Init(info))
     return plugin_host;
 
   NOTREACHED();  // Init is not expected to fail.
   return NULL;
 }
 
 void PpapiPluginProcessHost::OpenChannelToPlugin(Client* client) {
-  if (opening_channel()) {
+  if (child_process_host()->opening_channel()) {
     // The channel is already in the process of being opened.  Put
     // this "open channel" request into a queue of requests that will
     // be run once the channel is open.
     pending_requests_.push_back(client);
     return;
   }
 
   // We already have an open channel, send a request right away to plugin.
   RequestPluginChannel(client);
 }
 
 PpapiPluginProcessHost::PpapiPluginProcessHost(net::HostResolver* host_resolver)
     : BrowserChildProcessHost(content::PROCESS_TYPE_PPAPI_PLUGIN),
       filter_(new PepperMessageFilter(host_resolver)),
       network_observer_(new PluginNetworkObserver(this)),
       is_broker_(false),
       process_id_(ChildProcessHost::GenerateChildProcessUniqueId()) {
-  AddFilter(filter_.get());
+  child_process_host()->AddFilter(filter_.get());
 }
 
 PpapiPluginProcessHost::PpapiPluginProcessHost()
     : BrowserChildProcessHost(content::PROCESS_TYPE_PPAPI_BROKER),
       is_broker_(true),
       process_id_(ChildProcessHost::GenerateChildProcessUniqueId()) {
 }
 
 bool PpapiPluginProcessHost::Init(const content::PepperPluginInfo& info) {
   plugin_path_ = info.path;
   if (info.name.empty()) {
     set_name(plugin_path_.BaseName().LossyDisplayName());
   } else {
     set_name(UTF8ToUTF16(info.name));
   }
 
-  if (!CreateChannel())
+  if (!child_process_host()->CreateChannel())
     return false;
 
   const CommandLine& browser_command_line = *CommandLine::ForCurrentProcess();
   CommandLine::StringType plugin_launcher =
       browser_command_line.GetSwitchValueNative(switches::kPpapiPluginLauncher);
 
 #if defined(OS_LINUX)
   int flags = plugin_launcher.empty() ? ChildProcessHost::CHILD_ALLOW_SELF :
                                         ChildProcessHost::CHILD_NORMAL;
 #else
   int flags = ChildProcessHost::CHILD_NORMAL;
 #endif
   FilePath exe_path = ChildProcessHost::GetChildPath(flags);
   if (exe_path.empty())
     return false;
 
   CommandLine* cmd_line = new CommandLine(exe_path);
   cmd_line->AppendSwitchASCII(switches::kProcessType,
                               is_broker_ ? switches::kPpapiBrokerProcess
                                          : switches::kPpapiPluginProcess);
-  cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id());
+  cmd_line->AppendSwitchASCII(switches::kProcessChannelID,
+                              child_process_host()->channel_id());
 
   // These switches are forwarded to both plugin and broker pocesses.
   static const char* kCommonForwardSwitches[] = {
     switches::kVModule
   };
   cmd_line->CopySwitchesFrom(browser_command_line, kCommonForwardSwitches,
                              arraysize(kCommonForwardSwitches));
 
   if (!is_broker_) {
     // TODO(vtl): Stop passing flash args in the command line, on windows is
@@ skipping 37 matching lines @@
   // a hang. See the similar code in PluginProcessHost for more description.
   PpapiMsg_CreateChannel* msg = new PpapiMsg_CreateChannel(process_handle,
                                                            renderer_id);
   msg->set_unblock(true);
   if (Send(msg))
     sent_requests_.push(client);
   else
     client->OnChannelOpened(base::kNullProcessHandle, IPC::ChannelHandle());
 }
 
-bool PpapiPluginProcessHost::CanShutdown() {
-  return true;
-}
-
 void PpapiPluginProcessHost::OnProcessLaunched() {
 }
 
 bool PpapiPluginProcessHost::OnMessageReceived(const IPC::Message& msg) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(PpapiPluginProcessHost, msg)
     IPC_MESSAGE_HANDLER(PpapiHostMsg_ChannelCreated,
                         OnRendererPluginChannelCreated)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
@@ skipping 65 matching lines @@
   ::DuplicateHandle(::GetCurrentProcess(), plugin_process,
                     renderer_process, &renderers_plugin_handle,
                     0, FALSE, DUPLICATE_SAME_ACCESS);
 #elif defined(OS_POSIX)
   // Don't need to duplicate anything on POSIX since it's just a PID.
   base::ProcessHandle renderers_plugin_handle = plugin_process;
 #endif
 
   client->OnChannelOpened(renderers_plugin_handle, channel_handle);
 }