Make ChildProcessHost be used through an interface in content/public, instead of by inheritence.

BUG=98716
Review URL: http://codereview.chromium.org/8787004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@112878 0039d316-1c4b-4281-b951-d872f2087c98

19 files changed, 318 insertions, 234 deletions

diff --git a/content/browser/browser_child_process_host.cc b/content/browser/browser_child_process_host.cc
index 7744153..93c997b 100644
--- a/content/browser/browser_child_process_host.cc
+++ b/content/browser/browser_child_process_host.cc
@@ -17,7 +17,7 @@
 #include "content/browser/profiler_message_filter.h"
 #include "content/browser/renderer_host/resource_message_filter.h"
 #include "content/browser/trace_message_filter.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/plugin_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/child_process_data.h"
@@ -34,6 +34,8 @@
 #endif
 
 using content::BrowserThread;
+using content::ChildProcessHost;
+using content::ChildProcessHostImpl;
 
 namespace {
 
@@ -60,9 +62,9 @@ BrowserChildProcessHost::BrowserChildProcessHost(
 #endif
       disconnect_was_alive_(false) {
   data_.type = type;
-  data_.id = ChildProcessHost::GenerateChildProcessUniqueId();
+  data_.id = ChildProcessHostImpl::GenerateChildProcessUniqueId();
 
-  child_process_host_.reset(new ChildProcessHost(this));
+  child_process_host_.reset(ChildProcessHost::Create(this));
   child_process_host_->AddFilter(new TraceMessageFilter);
   child_process_host_->AddFilter(new ProfilerMessageFilter);
 
@@ -98,7 +100,7 @@ void BrowserChildProcessHost::Launch(
 #elif defined(OS_POSIX)
       use_zygote,
       environ,
-      child_process_host()->channel()->TakeClientFileDescriptor(),
+      child_process_host()->TakeClientFileDescriptor(),
 #endif
       cmd_line,
       &client_));
diff --git a/content/browser/browser_child_process_host.h b/content/browser/browser_child_process_host.h
index 2abb0bf..a4eca07 100644
--- a/content/browser/browser_child_process_host.h
+++ b/content/browser/browser_child_process_host.h
@@ -19,12 +19,14 @@
 #include "content/public/common/child_process_host_delegate.h"
 #include "ipc/ipc_message.h"
 
-class ChildProcessHost;
-
 namespace base {
 class WaitableEvent;
 }
 
+namespace content {
+class ChildProcessHost;
+}
+
 // Plugins/workers and other child processes that live on the IO thread should
 // derive from this class.
 //
@@ -122,7 +124,7 @@ class CONTENT_EXPORT BrowserChildProcessHost :
   // Sends the given notification on the UI thread.
   void Notify(int type);
 
-  ChildProcessHost* child_process_host() const {
+  content::ChildProcessHost* child_process_host() const {
     return child_process_host_.get();
   }
   void set_name(const string16& name) { data_.name = name; }
@@ -141,7 +143,7 @@ class CONTENT_EXPORT BrowserChildProcessHost :
   };
 
   content::ChildProcessData data_;
-  scoped_ptr<ChildProcessHost> child_process_host_;
+  scoped_ptr<content::ChildProcessHost> child_process_host_;
 
   ClientHook client_;
   scoped_ptr<ChildProcessLauncher> child_process_;
diff --git a/content/browser/gpu/gpu_process_host.cc b/content/browser/gpu/gpu_process_host.cc
index 3b18d38..9f0d735 100644
--- a/content/browser/gpu/gpu_process_host.cc
+++ b/content/browser/gpu/gpu_process_host.cc
@@ -17,7 +17,7 @@
 #include "content/browser/gpu/gpu_process_host_ui_shim.h"
 #include "content/browser/renderer_host/render_widget_host.h"
 #include "content/browser/renderer_host/render_widget_host_view.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/gpu/gpu_child_thread.h"
 #include "content/gpu/gpu_process.h"
@@ -35,6 +35,7 @@
 #endif
 
 using content::BrowserThread;
+using content::ChildProcessHost;
 
 bool GpuProcessHost::gpu_enabled_ = true;
 
@@ -319,15 +320,15 @@ GpuProcessHost::~GpuProcessHost() {
 }
 
 bool GpuProcessHost::Init() {
-  if (!child_process_host()->CreateChannel())
+  std::string channel_id = child_process_host()->CreateChannel();
+  if (channel_id.empty())
     return false;
 
   if (in_process_) {
     CommandLine::ForCurrentProcess()->AppendSwitch(
         switches::kDisableGpuWatchdog);
 
-    in_process_gpu_thread_.reset(new GpuMainThread(
-        child_process_host()->channel_id()));
+    in_process_gpu_thread_.reset(new GpuMainThread(channel_id));
 
     base::Thread::Options options;
 #if defined(OS_WIN)
@@ -343,7 +344,7 @@ bool GpuProcessHost::Init() {
     in_process_gpu_thread_->StartWithOptions(options);
 
     OnProcessLaunched();  // Fake a callback that the process is ready.
-  } else if (!LaunchGpuProcess())
+  } else if (!LaunchGpuProcess(channel_id))
     return false;
 
   return Send(new GpuMsg_Initialize());
@@ -358,7 +359,7 @@ void GpuProcessHost::RouteOnUIThread(const IPC::Message& message) {
 
 bool GpuProcessHost::Send(IPC::Message* msg) {
   DCHECK(CalledOnValidThread());
-  if (child_process_host()->opening_channel()) {
+  if (child_process_host()->IsChannelOpening()) {
     queued_messages_.push(msg);
     return true;
   }
@@ -543,7 +544,7 @@ bool GpuProcessHost::software_rendering() {
   return software_rendering_;
 }
 
-bool GpuProcessHost::LaunchGpuProcess() {
+bool GpuProcessHost::LaunchGpuProcess(const std::string& channel_id) {
   if (!gpu_enabled_ || g_gpu_crash_count >= kGpuMaxCrashCount) {
     SendOutstandingReplies();
     gpu_enabled_ = false;
@@ -568,8 +569,7 @@ bool GpuProcessHost::LaunchGpuProcess() {
 
   CommandLine* cmd_line = new CommandLine(exe_path);
   cmd_line->AppendSwitchASCII(switches::kProcessType, switches::kGpuProcess);
-  cmd_line->AppendSwitchASCII(switches::kProcessChannelID,
-                              child_process_host()->channel_id());
+  cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
 
   // Propagate relevant command line switches.
   static const char* const kSwitchNames[] = {
diff --git a/content/browser/gpu/gpu_process_host.h b/content/browser/gpu/gpu_process_host.h
index 073e8fd..479ebae 100644
--- a/content/browser/gpu/gpu_process_host.h
+++ b/content/browser/gpu/gpu_process_host.h
@@ -102,7 +102,7 @@ class GpuProcessHost : public BrowserChildProcessHost,
       gfx::PluginWindowHandle window, int32 renderer_id, int32 render_view_id);
   void OnGraphicsInfoCollected(const content::GPUInfo& gpu_info);
 
-  bool LaunchGpuProcess();
+  bool LaunchGpuProcess(const std::string& channel_id);
 
   void SendOutstandingReplies();
   void EstablishChannelError(
diff --git a/content/browser/plugin_data_remover_impl.cc b/content/browser/plugin_data_remover_impl.cc
index 38489d5..c41e913 100644
--- a/content/browser/plugin_data_remover_impl.cc
+++ b/content/browser/plugin_data_remover_impl.cc
@@ -10,12 +10,13 @@
 #include "base/version.h"
 #include "content/browser/plugin_process_host.h"
 #include "content/browser/plugin_service.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/plugin_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "webkit/plugins/npapi/plugin_group.h"
 
 using content::BrowserThread;
+using content::ChildProcessHostImpl;
 
 namespace {
 
@@ -93,7 +94,7 @@ class PluginDataRemoverImpl::Context
   // PluginProcessHost::Client methods.
   virtual int ID() OVERRIDE {
     // Generate a unique identifier for this PluginProcessHostClient.
-    return ChildProcessHost::GenerateChildProcessUniqueId();
+    return ChildProcessHostImpl::GenerateChildProcessUniqueId();
   }
 
   virtual bool OffTheRecord() OVERRIDE {
diff --git a/content/browser/plugin_loader_posix.cc b/content/browser/plugin_loader_posix.cc
index bc96427..26fe95e 100644
--- a/content/browser/plugin_loader_posix.cc
+++ b/content/browser/plugin_loader_posix.cc
@@ -8,12 +8,13 @@
 #include "base/message_loop.h"
 #include "base/message_loop_proxy.h"
 #include "base/metrics/histogram.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/utility_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "webkit/plugins/npapi/plugin_list.h"
 
 using content::BrowserThread;
+using content::ChildProcessHost;
 
 PluginLoaderPosix::PluginLoaderPosix()
     : next_load_index_(0) {
diff --git a/content/browser/plugin_process_host.cc b/content/browser/plugin_process_host.cc
index 293072d..4989477 100644
--- a/content/browser/plugin_process_host.cc
+++ b/content/browser/plugin_process_host.cc
@@ -22,7 +22,7 @@
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "content/browser/plugin_service.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/plugin_messages.h"
 #include "content/common/resource_messages.h"
 #include "content/public/browser/browser_thread.h"
@@ -36,6 +36,7 @@
 #include "ui/gfx/native_widget_types.h"
 
 using content::BrowserThread;
+using content::ChildProcessHost;
 
 #if defined(USE_X11)
 #include "ui/gfx/gtk_native_view_id_manager.h"
@@ -168,7 +169,8 @@ bool PluginProcessHost::Init(const webkit::WebPluginInfo& info,
   info_ = info;
   set_name(info_.name);
 
-  if (!child_process_host()->CreateChannel())
+  std::string channel_id = child_process_host()->CreateChannel();
+  if (channel_id.empty())
     return false;
 
   // Build command line for plugin. When we have a plugin launcher, we can't
@@ -235,8 +237,7 @@ bool PluginProcessHost::Init(const webkit::WebPluginInfo& info,
     cmd_line->AppendSwitchASCII(switches::kLang, locale);
   }
 
-  cmd_line->AppendSwitchASCII(switches::kProcessChannelID,
-                              child_process_host()->channel_id());
+  cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
 
 #if defined(OS_POSIX)
   base::environment_vector env;
@@ -366,7 +367,7 @@ void PluginProcessHost::CancelPendingRequestsForResourceContext(
 void PluginProcessHost::OpenChannelToPlugin(Client* client) {
   Notify(content::NOTIFICATION_CHILD_INSTANCE_CREATED);
   client->SetPluginInfo(info_);
-  if (child_process_host()->opening_channel()) {
+  if (child_process_host()->IsChannelOpening()) {
     // 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.
diff --git a/content/browser/ppapi_plugin_process_host.cc b/content/browser/ppapi_plugin_process_host.cc
index f4ccd33..f633842 100644
--- a/content/browser/ppapi_plugin_process_host.cc
+++ b/content/browser/ppapi_plugin_process_host.cc
@@ -11,7 +11,7 @@
 #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_host_impl.h"
 #include "content/common/child_process_messages.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/pepper_plugin_info.h"
@@ -20,6 +20,9 @@
 #include "net/base/network_change_notifier.h"
 #include "ppapi/proxy/ppapi_messages.h"
 
+using content::ChildProcessHost;
+using content::ChildProcessHostImpl;
+
 class PpapiPluginProcessHost::PluginNetworkObserver
     : public net::NetworkChangeNotifier::IPAddressObserver,
       public net::NetworkChangeNotifier::OnlineStateObserver {
@@ -85,7 +88,7 @@ PpapiPluginProcessHost* PpapiPluginProcessHost::CreateBrokerHost(
 }
 
 void PpapiPluginProcessHost::OpenChannelToPlugin(Client* client) {
-  if (child_process_host()->opening_channel()) {
+  if (child_process_host()->IsChannelOpening()) {
     // 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.
@@ -102,14 +105,14 @@ PpapiPluginProcessHost::PpapiPluginProcessHost(net::HostResolver* host_resolver)
       filter_(new PepperMessageFilter(host_resolver)),
       network_observer_(new PluginNetworkObserver(this)),
       is_broker_(false),
-      process_id_(ChildProcessHost::GenerateChildProcessUniqueId()) {
+      process_id_(ChildProcessHostImpl::GenerateChildProcessUniqueId()) {
   child_process_host()->AddFilter(filter_.get());
 }
 
 PpapiPluginProcessHost::PpapiPluginProcessHost()
     : BrowserChildProcessHost(content::PROCESS_TYPE_PPAPI_BROKER),
       is_broker_(true),
-      process_id_(ChildProcessHost::GenerateChildProcessUniqueId()) {
+      process_id_(ChildProcessHostImpl::GenerateChildProcessUniqueId()) {
 }
 
 bool PpapiPluginProcessHost::Init(const content::PepperPluginInfo& info) {
@@ -120,7 +123,8 @@ bool PpapiPluginProcessHost::Init(const content::PepperPluginInfo& info) {
     set_name(UTF8ToUTF16(info.name));
   }
 
-  if (!child_process_host()->CreateChannel())
+  std::string channel_id = child_process_host()->CreateChannel();
+  if (channel_id.empty())
     return false;
 
   const CommandLine& browser_command_line = *CommandLine::ForCurrentProcess();
@@ -141,8 +145,7 @@ bool PpapiPluginProcessHost::Init(const content::PepperPluginInfo& info) {
   cmd_line->AppendSwitchASCII(switches::kProcessType,
                               is_broker_ ? switches::kPpapiBrokerProcess
                                          : switches::kPpapiPluginProcess);
-  cmd_line->AppendSwitchASCII(switches::kProcessChannelID,
-                              child_process_host()->channel_id());
+  cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
 
   // These switches are forwarded to both plugin and broker pocesses.
   static const char* kCommonForwardSwitches[] = {
diff --git a/content/browser/renderer_host/mock_render_process_host.cc b/content/browser/renderer_host/mock_render_process_host.cc
index bc0d9d8..9f3bca7 100644
--- a/content/browser/renderer_host/mock_render_process_host.cc
+++ b/content/browser/renderer_host/mock_render_process_host.cc
@@ -9,16 +9,18 @@
 #include "base/time.h"
 #include "content/browser/child_process_security_policy.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_types.h"
 
+using content::ChildProcessHostImpl;
+
 MockRenderProcessHost::MockRenderProcessHost(
     content::BrowserContext* browser_context)
         : transport_dib_(NULL),
           bad_msg_count_(0),
           factory_(NULL),
-          id_(ChildProcessHost::GenerateChildProcessUniqueId()),
+          id_(ChildProcessHostImpl::GenerateChildProcessUniqueId()),
           browser_context_(browser_context),
           max_page_id_(-1),
           fast_shutdown_started_(false) {
diff --git a/content/browser/renderer_host/render_message_filter.cc b/content/browser/renderer_host/render_message_filter.cc
index f84b968..fe937b2 100644
--- a/content/browser/renderer_host/render_message_filter.cc
+++ b/content/browser/renderer_host/render_message_filter.cc
@@ -29,7 +29,7 @@
 #include "content/browser/renderer_host/render_widget_helper.h"
 #include "content/browser/resource_context.h"
 #include "content/browser/user_metrics.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/child_process_messages.h"
 #include "content/common/desktop_notification_messages.h"
 #include "content/common/view_messages.h"
@@ -67,6 +67,7 @@
 #endif
 
 using content::BrowserThread;
+using content::ChildProcessHostImpl;
 using content::PluginServiceFilter;
 using net::CookieStore;
 
@@ -686,7 +687,8 @@ void RenderMessageFilter::OnCheckNotificationPermission(
 void RenderMessageFilter::OnAllocateSharedMemory(
     uint32 buffer_size,
     base::SharedMemoryHandle* handle) {
-  ChildProcessHost::AllocateSharedMemory(buffer_size, peer_handle(), handle);
+  ChildProcessHostImpl::AllocateSharedMemory(
+      buffer_size, peer_handle(), handle);
 }
 
 net::URLRequestContext* RenderMessageFilter::GetRequestContextForURL(
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 4f05460..009b731 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -78,7 +78,7 @@
 #include "content/browser/user_metrics.h"
 #include "content/browser/webui/web_ui_factory.h"
 #include "content/browser/worker_host/worker_message_filter.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/child_process_messages.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/public/browser/notification_service.h"
@@ -112,6 +112,8 @@
 #include "third_party/skia/include/core/SkBitmap.h"
 
 using content::BrowserThread;
+using content::ChildProcessHost;
+using content::ChildProcessHostImpl;
 
 // This class creates the IO thread for the renderer when running in
 // single-process mode.  It's not used in multi-process mode.
@@ -283,7 +285,7 @@ RenderProcessHostImpl::RenderProcessHostImpl(
                 this, &RenderProcessHostImpl::ClearTransportDIBCache)),
           accessibility_enabled_(false),
           is_initialized_(false),
-          id_(ChildProcessHost::GenerateChildProcessUniqueId()),
+          id_(ChildProcessHostImpl::GenerateChildProcessUniqueId()),
           browser_context_(browser_context),
           sudden_termination_allowed_(true),
           ignore_input_events_(false) {
@@ -387,7 +389,7 @@ bool RenderProcessHostImpl::Init(bool is_accessibility_enabled) {
 
   // Setup the IPC channel.
   const std::string channel_id =
-      ChildProcessHost::GenerateRandomChannelID(this);
+      ChildProcessHostImpl::GenerateRandomChannelID(this);
   channel_.reset(new IPC::ChannelProxy(
       channel_id, IPC::Channel::MODE_SERVER, this,
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)));
diff --git a/content/browser/renderer_host/resource_dispatcher_host_unittest.cc b/content/browser/renderer_host/resource_dispatcher_host_unittest.cc
index ae610be..5c216fa 100644
--- a/content/browser/renderer_host/resource_dispatcher_host_unittest.cc
+++ b/content/browser/renderer_host/resource_dispatcher_host_unittest.cc
@@ -21,7 +21,7 @@
 #include "content/browser/renderer_host/resource_dispatcher_host_request_info.h"
 #include "content/browser/renderer_host/resource_handler.h"
 #include "content/browser/renderer_host/resource_message_filter.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/resource_messages.h"
 #include "content/common/view_messages.h"
 #include "content/public/common/resource_response.h"
@@ -36,6 +36,7 @@
 
 using content::BrowserThread;
 using content::BrowserThreadImpl;
+using content::ChildProcessHostImpl;
 
 // TODO(eroman): Write unit tests for SafeBrowsing that exercise
 //               SafeBrowsingResourceHandler.
@@ -162,7 +163,7 @@ class ForwardingFilter : public ResourceMessageFilter {
  public:
   explicit ForwardingFilter(IPC::Message::Sender* dest)
     : ResourceMessageFilter(
-        ChildProcessHost::GenerateChildProcessUniqueId(),
+        ChildProcessHostImpl::GenerateChildProcessUniqueId(),
         content::PROCESS_TYPE_RENDERER,
         content::MockResourceContext::GetInstance(),
         new MockURLRequestContextSelector(
diff --git a/content/browser/utility_process_host.cc b/content/browser/utility_process_host.cc
index 8bc2234..998f8a5 100644
--- a/content/browser/utility_process_host.cc
+++ b/content/browser/utility_process_host.cc
@@ -9,7 +9,7 @@
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/utility_messages.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/common/content_switches.h"
@@ -18,6 +18,7 @@
 #include "webkit/plugins/plugin_switches.h"
 
 using content::BrowserThread;
+using content::ChildProcessHost;
 
 UtilityProcessHost::Client::Client() {
 }
@@ -87,7 +88,8 @@ bool UtilityProcessHost::StartProcess() {
   // launches a UtilityProcessHost.
   set_name(ASCIIToUTF16("utility process"));
 
-  if (!child_process_host()->CreateChannel())
+  std::string channel_id = child_process_host()->CreateChannel();
+  if (channel_id.empty())
     return false;
 
   FilePath exe_path = GetUtilityProcessCmd();
@@ -99,8 +101,7 @@ bool UtilityProcessHost::StartProcess() {
   CommandLine* cmd_line = new CommandLine(exe_path);
   cmd_line->AppendSwitchASCII(switches::kProcessType,
                               switches::kUtilityProcess);
-  cmd_line->AppendSwitchASCII(switches::kProcessChannelID,
-                              child_process_host()->channel_id());
+  cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
   std::string locale =
       content::GetContentClient()->browser()->GetApplicationLocale();
   cmd_line->AppendSwitchASCII(switches::kLang, locale);
diff --git a/content/browser/worker_host/worker_process_host.cc b/content/browser/worker_host/worker_process_host.cc
index 68d75c9..178de54 100644
--- a/content/browser/worker_host/worker_process_host.cc
+++ b/content/browser/worker_host/worker_process_host.cc
@@ -31,7 +31,7 @@
 #include "content/browser/worker_host/message_port_service.h"
 #include "content/browser/worker_host/worker_message_filter.h"
 #include "content/browser/worker_host/worker_service.h"
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 #include "content/common/debug_flags.h"
 #include "content/common/view_messages.h"
 #include "content/common/worker_messages.h"
@@ -49,6 +49,7 @@
 #include "webkit/glue/resource_type.h"
 
 using content::BrowserThread;
+using content::ChildProcessHost;
 
 namespace {
 
@@ -112,7 +113,8 @@ WorkerProcessHost::~WorkerProcessHost() {
 }
 
 bool WorkerProcessHost::Init(int render_process_id) {
-  if (!child_process_host()->CreateChannel())
+  std::string channel_id = child_process_host()->CreateChannel();
+  if (channel_id.empty())
     return false;
 
 #if defined(OS_LINUX)
@@ -127,8 +129,7 @@ bool WorkerProcessHost::Init(int render_process_id) {
 
   CommandLine* cmd_line = new CommandLine(exe_path);
   cmd_line->AppendSwitchASCII(switches::kProcessType, switches::kWorkerProcess);
-  cmd_line->AppendSwitchASCII(switches::kProcessChannelID,
-                              child_process_host()->channel_id());
+  cmd_line->AppendSwitchASCII(switches::kProcessChannelID, channel_id);
   std::string locale =
       content::GetContentClient()->browser()->GetApplicationLocale();
   cmd_line->AppendSwitchASCII(switches::kLang, locale);
diff --git a/content/common/child_process_host.h b/content/common/child_process_host.h
deleted file mode 100644
index 7f044f4..0000000
--- a/content/common/child_process_host.h
+++ /dev/null
@@ -1,145 +0,0 @@
-// 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.
-
-#ifndef CONTENT_COMMON_CHILD_PROCESS_HOST_H_
-#define CONTENT_COMMON_CHILD_PROCESS_HOST_H_
-#pragma once
-
-#include <string>
-#include <vector>
-
-#include "build/build_config.h"
-
-#include "base/basictypes.h"
-#include "base/memory/scoped_ptr.h"
-#include "base/memory/singleton.h"
-#include "base/shared_memory.h"
-#include "base/string16.h"
-#include "content/common/content_export.h"
-#include "ipc/ipc_channel_proxy.h"
-
-class FilePath;
-
-namespace content {
-class ChildProcessHostDelegate;
-}
-
-// Provides common functionality for hosting a child process and processing IPC
-// messages between the host and the child process. Users are responsible
-// for the actual launching and terminating of the child processes.
-class CONTENT_EXPORT ChildProcessHost : public IPC::Channel::Listener,
-                                        public IPC::Message::Sender {
- public:
-  // These flags may be passed to GetChildPath in order to alter its behavior,
-  // causing it to return a child path more suited to a specific task.
-  enum {
-    // No special behavior requested.
-    CHILD_NORMAL = 0,
-
-#if defined(OS_LINUX)
-    // Indicates that the child execed after forking may be execced from
-    // /proc/self/exe rather than using the "real" app path. This prevents
-    // autoupdate from confusing us if it changes the file out from under us.
-    // You will generally want to set this on Linux, except when there is an
-    // override to the command line (for example, we're forking a renderer in
-    // gdb). In this case, you'd use GetChildPath to get the real executable
-    // file name, and then prepend the GDB command to the command line.
-    CHILD_ALLOW_SELF = 1 << 0,
-#elif defined(OS_MACOSX)
-
-    // Requests that the child run in a process that does not have the
-    // PIE (position-independent executable) bit set, effectively disabling
-    // ASLR. For process types that need to allocate a large contiguous
-    // region, ASLR may not leave a large enough "hole" for the purpose. This
-    // option should be used sparingly, and only when absolutely necessary.
-    // This option is currently incompatible with CHILD_ALLOW_HEAP_EXECUTION.
-    CHILD_NO_PIE = 1 << 1,
-
-    // Requests that the child run in a process that does not protect the
-    // heap against execution. Normally, heap pages may be made executable
-    // with mprotect, so this mode should be used sparingly. It is intended
-    // for processes that may host plug-ins that expect an executable heap
-    // without having to call mprotect. This option is currently incompatible
-    // with CHILD_NO_PIE.
-    CHILD_ALLOW_HEAP_EXECUTION = 1 << 2,
-#endif
-  };
-
-  virtual ~ChildProcessHost();
-
-  // Returns the pathname to be used for a child process.  If a subprocess
-  // pathname was specified on the command line, that will be used.  Otherwise,
-  // the default child process pathname will be returned.  On most platforms,
-  // this will be the same as the currently-executing process.
-  //
-  // The |flags| argument accepts one or more flags such as CHILD_ALLOW_SELF
-  // and CHILD_ALLOW_HEAP_EXECUTION as defined above. Pass only CHILD_NORMAL
-  // if none of these special behaviors are required.
-  //
-  // On failure, returns an empty FilePath.
-  static FilePath GetChildPath(int flags);
-
-  explicit ChildProcessHost(content::ChildProcessHostDelegate* delegate);
-
-  // IPC::Message::Sender implementation.
-  virtual bool Send(IPC::Message* message) OVERRIDE;
-
-  // Adds an IPC message filter.  A reference will be kept to the filter.
-  void AddFilter(IPC::ChannelProxy::MessageFilter* filter);
-
-  // Public and static for reuse by RenderMessageFilter.
-  static void AllocateSharedMemory(
-      uint32 buffer_size, base::ProcessHandle child_process,
-      base::SharedMemoryHandle* handle);
-
-  // Generates a unique channel name for a child process.
-  // The "instance" pointer value is baked into the channel id.
-  static std::string GenerateRandomChannelID(void* instance);
-
-  // Returns a unique ID to identify a child process. On construction, this
-  // function will be used to generate the id_, but it is also used to generate
-  // IDs for the RenderProcessHost, which doesn't inherit from us, and whose IDs
-  // must be unique for all child processes.
-  //
-  // This function is threadsafe since RenderProcessHost is on the UI thread,
-  // but normally this will be used on the IO thread.
-  static int GenerateChildProcessUniqueId();
-
-  // Send the shutdown message to the child process.
-  // Does not check if CanShutdown is true.
-  void ForceShutdown();
-
-  // Creates the IPC channel.  Returns true iff it succeeded.
-  bool CreateChannel();
-
-  bool opening_channel() { return opening_channel_; }
-  const std::string& channel_id() { return channel_id_; }
-  IPC::Channel* channel() { return channel_.get(); }
-
- private:
-  // IPC::Channel::Listener methods:
-  virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
-  virtual void OnChannelConnected(int32 peer_pid) OVERRIDE;
-  virtual void OnChannelError() OVERRIDE;
-
-  // Message handlers:
-  void OnShutdownRequest();
-  void OnAllocateSharedMemory(uint32 buffer_size,
-                              base::SharedMemoryHandle* handle);
-
-  content::ChildProcessHostDelegate* delegate_;
-  base::ProcessHandle peer_handle_;
-  bool opening_channel_;  // True while we're waiting the channel to be opened.
-  scoped_ptr<IPC::Channel> channel_;
-  std::string channel_id_;
-
-  // Holds all the IPC message filters.  Since this object lives on the IO
-  // thread, we don't have a IPC::ChannelProxy and so we manage filters
-  // manually.
-  std::vector<scoped_refptr<IPC::ChannelProxy::MessageFilter> > filters_;
-
-  DISALLOW_COPY_AND_ASSIGN(ChildProcessHost);
-};
-
-#endif  // CONTENT_COMMON_CHILD_PROCESS_HOST_H_
diff --git a/content/common/child_process_host.cc b/content/common/child_process_host_impl.cc
index 002e016..1e332ce 100644
--- a/content/common/child_process_host.cc
+++ b/content/common/child_process_host_impl.cc
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "content/common/child_process_host.h"
+#include "content/common/child_process_host_impl.h"
 
 #include <limits>
 
@@ -74,29 +74,11 @@ FilePath TransformPathForFeature(const FilePath& path,
 }  // namespace
 #endif  // OS_MACOSX
 
-ChildProcessHost::ChildProcessHost(content::ChildProcessHostDelegate* delegate)
-    : delegate_(delegate),
-      peer_handle_(base::kNullProcessHandle),
-      opening_channel_(false) {
-#if defined(OS_WIN)
-  AddFilter(new FontCacheDispatcher());
-#endif
-}
+namespace content {
 
-ChildProcessHost::~ChildProcessHost() {
-  for (size_t i = 0; i < filters_.size(); ++i) {
-    filters_[i]->OnChannelClosing();
-    filters_[i]->OnFilterRemoved();
-  }
-
-  base::CloseProcessHandle(peer_handle_);
-}
-
-void ChildProcessHost::AddFilter(IPC::ChannelProxy::MessageFilter* filter) {
-  filters_.push_back(filter);
-
-  if (channel_.get())
-    filter->OnFilterAdded(channel_.get());
+// static
+ChildProcessHost* ChildProcessHost::Create(ChildProcessHostDelegate* delegate) {
+  return new ChildProcessHostImpl(delegate);
 }
 
 // static
@@ -143,16 +125,41 @@ FilePath ChildProcessHost::GetChildPath(int flags) {
   return child_path;
 }
 
-void ChildProcessHost::ForceShutdown() {
+ChildProcessHostImpl::ChildProcessHostImpl(ChildProcessHostDelegate* delegate)
+    : delegate_(delegate),
+      peer_handle_(base::kNullProcessHandle),
+      opening_channel_(false) {
+#if defined(OS_WIN)
+  AddFilter(new FontCacheDispatcher());
+#endif
+}
+
+ChildProcessHostImpl::~ChildProcessHostImpl() {
+  for (size_t i = 0; i < filters_.size(); ++i) {
+    filters_[i]->OnChannelClosing();
+    filters_[i]->OnFilterRemoved();
+  }
+
+  base::CloseProcessHandle(peer_handle_);
+}
+
+void ChildProcessHostImpl::AddFilter(IPC::ChannelProxy::MessageFilter* filter) {
+  filters_.push_back(filter);
+
+  if (channel_.get())
+    filter->OnFilterAdded(channel_.get());
+}
+
+void ChildProcessHostImpl::ForceShutdown() {
   Send(new ChildProcessMsg_Shutdown());
 }
 
-bool ChildProcessHost::CreateChannel() {
+std::string ChildProcessHostImpl::CreateChannel() {
   channel_id_ = GenerateRandomChannelID(this);
   channel_.reset(new IPC::Channel(
       channel_id_, IPC::Channel::MODE_SERVER, this));
   if (!channel_->Connect())
-    return false;
+    return std::string();
 
   for (size_t i = 0; i < filters_.size(); ++i)
     filters_[i]->OnFilterAdded(channel_.get());
@@ -167,10 +174,20 @@ bool ChildProcessHost::CreateChannel() {
 
   opening_channel_ = true;
 
-  return true;
+  return channel_id_;
 }
 
-bool ChildProcessHost::Send(IPC::Message* message) {
+bool ChildProcessHostImpl::IsChannelOpening() {
+  return opening_channel_;
+}
+
+#if defined(OS_POSIX)
+int ChildProcessHostImpl::TakeClientFileDescriptor() {
+  return channel_->TakeClientFileDescriptor();
+}
+#endif
+
+bool ChildProcessHostImpl::Send(IPC::Message* message) {
   if (!channel_.get()) {
     delete message;
     return false;
@@ -178,7 +195,7 @@ bool ChildProcessHost::Send(IPC::Message* message) {
   return channel_->Send(message);
 }
 
-void ChildProcessHost::AllocateSharedMemory(
+void ChildProcessHostImpl::AllocateSharedMemory(
       uint32 buffer_size, base::ProcessHandle child_process_handle,
       base::SharedMemoryHandle* shared_memory_handle) {
   base::SharedMemory shared_buf;
@@ -190,7 +207,7 @@ void ChildProcessHost::AllocateSharedMemory(
   shared_buf.GiveToProcess(child_process_handle, shared_memory_handle);
 }
 
-std::string ChildProcessHost::GenerateRandomChannelID(void* instance) {
+std::string ChildProcessHostImpl::GenerateRandomChannelID(void* instance) {
   // Note: the string must start with the current process id, this is how
   // child processes determine the pid of the parent.
   // Build the channel ID.  This is composed of a unique identifier for the
@@ -202,13 +219,13 @@ std::string ChildProcessHost::GenerateRandomChannelID(void* instance) {
                             base::RandInt(0, std::numeric_limits<int>::max()));
 }
 
-int ChildProcessHost::GenerateChildProcessUniqueId() {
+int ChildProcessHostImpl::GenerateChildProcessUniqueId() {
   // This function must be threadsafe.
   static base::subtle::Atomic32 last_unique_child_id = 0;
   return base::subtle::NoBarrier_AtomicIncrement(&last_unique_child_id, 1);
 }
 
-bool ChildProcessHost::OnMessageReceived(const IPC::Message& msg) {
+bool ChildProcessHostImpl::OnMessageReceived(const IPC::Message& msg) {
 #ifdef IPC_MESSAGE_LOG_ENABLED
   IPC::Logging* logger = IPC::Logging::GetInstance();
   if (msg.type() == IPC_LOGGING_ID) {
@@ -230,7 +247,7 @@ bool ChildProcessHost::OnMessageReceived(const IPC::Message& msg) {
 
   if (!handled) {
     handled = true;
-    IPC_BEGIN_MESSAGE_MAP(ChildProcessHost, msg)
+    IPC_BEGIN_MESSAGE_MAP(ChildProcessHostImpl, msg)
       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_ShutdownRequest,
                           OnShutdownRequest)
       IPC_MESSAGE_HANDLER(ChildProcessHostMsg_SyncAllocateSharedMemory,
@@ -249,7 +266,7 @@ bool ChildProcessHost::OnMessageReceived(const IPC::Message& msg) {
   return handled;
 }
 
-void ChildProcessHost::OnChannelConnected(int32 peer_pid) {
+void ChildProcessHostImpl::OnChannelConnected(int32 peer_pid) {
   if (!base::OpenProcessHandle(peer_pid, &peer_handle_)) {
     NOTREACHED();
   }
@@ -259,7 +276,7 @@ void ChildProcessHost::OnChannelConnected(int32 peer_pid) {
     filters_[i]->OnChannelConnected(peer_pid);
 }
 
-void ChildProcessHost::OnChannelError() {
+void ChildProcessHostImpl::OnChannelError() {
   opening_channel_ = false;
   delegate_->OnChannelError();
 
@@ -270,13 +287,15 @@ void ChildProcessHost::OnChannelError() {
   delegate_->OnChildDisconnected();
 }
 
-void ChildProcessHost::OnAllocateSharedMemory(
+void ChildProcessHostImpl::OnAllocateSharedMemory(
     uint32 buffer_size,
     base::SharedMemoryHandle* handle) {
   AllocateSharedMemory(buffer_size, peer_handle_, handle);
 }
 
-void ChildProcessHost::OnShutdownRequest() {
+void ChildProcessHostImpl::OnShutdownRequest() {
   if (delegate_->CanShutdown())
     Send(new ChildProcessMsg_Shutdown());
 }
+
+}  // namespace content
diff --git a/content/common/child_process_host_impl.h b/content/common/child_process_host_impl.h
new file mode 100644
index 0000000..32736f3
--- /dev/null
+++ b/content/common/child_process_host_impl.h
@@ -0,0 +1,93 @@
+// 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.
+
+#ifndef CONTENT_COMMON_CHILD_PROCESS_HOST_IMPL_H_
+#define CONTENT_COMMON_CHILD_PROCESS_HOST_IMPL_H_
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "build/build_config.h"
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
+#include "base/shared_memory.h"
+#include "base/string16.h"
+#include "content/public/common/child_process_host.h"
+
+class FilePath;
+
+namespace content {
+class ChildProcessHostDelegate;
+
+// Provides common functionality for hosting a child process and processing IPC
+// messages between the host and the child process. Users are responsible
+// for the actual launching and terminating of the child processes.
+class CONTENT_EXPORT ChildProcessHostImpl : public ChildProcessHost,
+                                            public IPC::Channel::Listener {
+ public:
+  virtual ~ChildProcessHostImpl();
+
+  // Public and static for reuse by RenderMessageFilter.
+  static void AllocateSharedMemory(
+      uint32 buffer_size, base::ProcessHandle child_process,
+      base::SharedMemoryHandle* handle);
+
+  // Generates a unique channel name for a child process.
+  // The "instance" pointer value is baked into the channel id.
+  static std::string GenerateRandomChannelID(void* instance);
+
+  // Returns a unique ID to identify a child process. On construction, this
+  // function will be used to generate the id_, but it is also used to generate
+  // IDs for the RenderProcessHost, which doesn't inherit from us, and whose IDs
+  // must be unique for all child processes.
+  //
+  // This function is threadsafe since RenderProcessHost is on the UI thread,
+  // but normally this will be used on the IO thread.
+  static int GenerateChildProcessUniqueId();
+
+  // ChildProcessHost implementation
+  virtual bool Send(IPC::Message* message) OVERRIDE;
+  virtual void ForceShutdown() OVERRIDE;
+  virtual std::string CreateChannel() OVERRIDE;
+  virtual bool IsChannelOpening() OVERRIDE;
+  virtual void AddFilter(IPC::ChannelProxy::MessageFilter* filter) OVERRIDE;
+#if defined(OS_POSIX)
+  virtual int TakeClientFileDescriptor() OVERRIDE;
+#endif
+
+ private:
+  friend class ChildProcessHost;
+
+  explicit ChildProcessHostImpl(ChildProcessHostDelegate* delegate);
+
+  // IPC::Channel::Listener methods:
+  virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
+  virtual void OnChannelConnected(int32 peer_pid) OVERRIDE;
+  virtual void OnChannelError() OVERRIDE;
+
+  // Message handlers:
+  void OnShutdownRequest();
+  void OnAllocateSharedMemory(uint32 buffer_size,
+                              base::SharedMemoryHandle* handle);
+
+  ChildProcessHostDelegate* delegate_;
+  base::ProcessHandle peer_handle_;
+  bool opening_channel_;  // True while we're waiting the channel to be opened.
+  scoped_ptr<IPC::Channel> channel_;
+  std::string channel_id_;
+
+  // Holds all the IPC message filters.  Since this object lives on the IO
+  // thread, we don't have a IPC::ChannelProxy and so we manage filters
+  // manually.
+  std::vector<scoped_refptr<IPC::ChannelProxy::MessageFilter> > filters_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChildProcessHostImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_CHILD_PROCESS_HOST_IMPL_H_
diff --git a/content/content_common.gypi b/content/content_common.gypi
index a9bdb55..29f17a2 100644
--- a/content/content_common.gypi
+++ b/content/content_common.gypi
@@ -29,6 +29,7 @@
   ],
   'sources': [
     'public/common/bindings_policy.h',
+    'public/common/child_process_host.h',
     'public/common/child_process_host_delegate.h',
     'public/common/child_process_sandbox_support_linux.h',
     'public/common/content_constants.cc',
@@ -82,8 +83,8 @@
     'common/appcache_messages.h',
     'common/child_process.cc',
     'common/child_process.h',
-    'common/child_process_host.cc',
-    'common/child_process_host.h',
+    'common/child_process_host_impl.cc',
+    'common/child_process_host_impl.h',
     'common/child_process_messages.h',
     'common/child_process_sandbox_support_impl_linux.cc',
     'common/child_process_sandbox_support_impl_linux.h',
diff --git a/content/public/common/child_process_host.h b/content/public/common/child_process_host.h
new file mode 100644
index 0000000..31839fc
--- /dev/null
+++ b/content/public/common/child_process_host.h
@@ -0,0 +1,97 @@
+// 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.
+
+#ifndef CONTENT_PULIC_COMMON_CHILD_PROCESS_HOST_H_
+#define CONTENT_PULIC_COMMON_CHILD_PROCESS_HOST_H_
+#pragma once
+
+#include "build/build_config.h"
+#include "content/common/content_export.h"
+#include "ipc/ipc_channel_proxy.h"
+
+class FilePath;
+
+namespace content {
+
+class ChildProcessHostDelegate;
+
+// Interface that all users of ChildProcessHost need to provide.
+class ChildProcessHost : public IPC::Message::Sender {
+ public:
+  virtual ~ChildProcessHost() {}
+
+  // Used to create a child process host. The delegate must outlive this object.
+  CONTENT_EXPORT static ChildProcessHost* Create(
+      ChildProcessHostDelegate* delegate);
+
+  // These flags may be passed to GetChildPath in order to alter its behavior,
+  // causing it to return a child path more suited to a specific task.
+  enum {
+    // No special behavior requested.
+    CHILD_NORMAL = 0,
+
+#if defined(OS_LINUX)
+    // Indicates that the child execed after forking may be execced from
+    // /proc/self/exe rather than using the "real" app path. This prevents
+    // autoupdate from confusing us if it changes the file out from under us.
+    // You will generally want to set this on Linux, except when there is an
+    // override to the command line (for example, we're forking a renderer in
+    // gdb). In this case, you'd use GetChildPath to get the real executable
+    // file name, and then prepend the GDB command to the command line.
+    CHILD_ALLOW_SELF = 1 << 0,
+#elif defined(OS_MACOSX)
+
+    // Requests that the child run in a process that does not have the
+    // PIE (position-independent executable) bit set, effectively disabling
+    // ASLR. For process types that need to allocate a large contiguous
+    // region, ASLR may not leave a large enough "hole" for the purpose. This
+    // option should be used sparingly, and only when absolutely necessary.
+    // This option is currently incompatible with CHILD_ALLOW_HEAP_EXECUTION.
+    CHILD_NO_PIE = 1 << 1,
+
+    // Requests that the child run in a process that does not protect the
+    // heap against execution. Normally, heap pages may be made executable
+    // with mprotect, so this mode should be used sparingly. It is intended
+    // for processes that may host plug-ins that expect an executable heap
+    // without having to call mprotect. This option is currently incompatible
+    // with CHILD_NO_PIE.
+    CHILD_ALLOW_HEAP_EXECUTION = 1 << 2,
+#endif
+  };
+
+  // Returns the pathname to be used for a child process.  If a subprocess
+  // pathname was specified on the command line, that will be used.  Otherwise,
+  // the default child process pathname will be returned.  On most platforms,
+  // this will be the same as the currently-executing process.
+  //
+  // The |flags| argument accepts one or more flags such as CHILD_ALLOW_SELF
+  // and CHILD_ALLOW_HEAP_EXECUTION as defined above. Pass only CHILD_NORMAL
+  // if none of these special behaviors are required.
+  //
+  // On failure, returns an empty FilePath.
+  CONTENT_EXPORT static FilePath GetChildPath(int flags);
+
+  // Send the shutdown message to the child process.
+  // Does not check with the delegate's CanShutdown.
+  virtual void ForceShutdown() = 0;
+
+  // Creates the IPC channel.  Returns the channel id if it succeeded, an
+  // empty string otherwise
+  virtual std::string CreateChannel() = 0;
+
+  // Returns true iff the IPC channel is currently being opened;
+  virtual bool IsChannelOpening() = 0;
+
+  // Adds an IPC message filter.  A reference will be kept to the filter.
+  virtual void AddFilter(IPC::ChannelProxy::MessageFilter* filter) = 0;
+
+#if defined(OS_POSIX)
+  // See IPC::Channel::TakeClientFileDescriptor.
+  virtual int TakeClientFileDescriptor() = 0;
+#endif
+};
+
+};  // namespace content
+
+#endif  // CONTENT_PULIC_COMMON_CHILD_PROCESS_HOST_H_