Unify the three places that patch font loading for PDFium on Windows.

content/child/child_thread.cc

Index: content/child/child_thread.cc
diff --git a/content/child/child_thread.cc b/content/child/child_thread.cc
deleted file mode 100644
index 82caa772f91a5d3357e66fabf4ab4b4afff87e60..0000000000000000000000000000000000000000
--- a/content/child/child_thread.cc
+++ /dev/null
@@ -1,629 +0,0 @@
-// 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/child/child_thread.h"
-
-#include <signal.h>
-
-#include <string>
-
-#include "base/allocator/allocator_extension.h"
-#include "base/base_switches.h"
-#include "base/basictypes.h"
-#include "base/command_line.h"
-#include "base/debug/leak_annotations.h"
-#include "base/lazy_instance.h"
-#include "base/logging.h"
-#include "base/message_loop/message_loop.h"
-#include "base/message_loop/timer_slack.h"
-#include "base/process/kill.h"
-#include "base/process/process_handle.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_util.h"
-#include "base/synchronization/condition_variable.h"
-#include "base/synchronization/lock.h"
-#include "base/threading/thread_local.h"
-#include "base/tracked_objects.h"
-#include "components/tracing/child_trace_message_filter.h"
-#include "content/child/bluetooth/bluetooth_message_filter.h"
-#include "content/child/child_discardable_shared_memory_manager.h"
-#include "content/child/child_gpu_memory_buffer_manager.h"
-#include "content/child/child_histogram_message_filter.h"
-#include "content/child/child_process.h"
-#include "content/child/child_resource_message_filter.h"
-#include "content/child/child_shared_bitmap_manager.h"
-#include "content/child/fileapi/file_system_dispatcher.h"
-#include "content/child/fileapi/webfilesystem_impl.h"
-#include "content/child/geofencing/geofencing_message_filter.h"
-#include "content/child/mojo/mojo_application.h"
-#include "content/child/navigator_connect/navigator_connect_dispatcher.h"
-#include "content/child/notifications/notification_dispatcher.h"
-#include "content/child/power_monitor_broadcast_source.h"
-#include "content/child/push_messaging/push_dispatcher.h"
-#include "content/child/quota_dispatcher.h"
-#include "content/child/quota_message_filter.h"
-#include "content/child/resource_dispatcher.h"
-#include "content/child/service_worker/service_worker_message_filter.h"
-#include "content/child/thread_safe_sender.h"
-#include "content/child/websocket_dispatcher.h"
-#include "content/common/child_process_messages.h"
-#include "content/public/common/content_switches.h"
-#include "ipc/ipc_logging.h"
-#include "ipc/ipc_switches.h"
-#include "ipc/ipc_sync_channel.h"
-#include "ipc/ipc_sync_message_filter.h"
-#include "ipc/mojo/ipc_channel_mojo.h"
-
-#if defined(OS_WIN)
-#include "content/common/handle_enumerator_win.h"
-#endif
-
-#if defined(TCMALLOC_TRACE_MEMORY_SUPPORTED)
-#include "third_party/tcmalloc/chromium/src/gperftools/heap-profiler.h"
-#endif
-
-using tracked_objects::ThreadData;
-
-namespace content {
-namespace {
-
-// How long to wait for a connection to the browser process before giving up.
-const int kConnectionTimeoutS = 15;
-
-base::LazyInstance<base::ThreadLocalPointer<ChildThread> > g_lazy_tls =
-    LAZY_INSTANCE_INITIALIZER;
-
-// This isn't needed on Windows because there the sandbox's job object
-// terminates child processes automatically. For unsandboxed processes (i.e.
-// plugins), PluginThread has EnsureTerminateMessageFilter.
-#if defined(OS_POSIX)
-
-// TODO(earthdok): Re-enable on CrOS http://crbug.com/360622
-#if (defined(ADDRESS_SANITIZER) || defined(LEAK_SANITIZER) || \
-     defined(MEMORY_SANITIZER) || defined(THREAD_SANITIZER) || \
-     defined(UNDEFINED_SANITIZER)) && !defined(OS_CHROMEOS)
-// A thread delegate that waits for |duration| and then exits the process with
-// _exit(0).
-class WaitAndExitDelegate : public base::PlatformThread::Delegate {
- public:
-  explicit WaitAndExitDelegate(base::TimeDelta duration)
-      : duration_(duration) {}
-
-  void ThreadMain() override {
-    base::PlatformThread::Sleep(duration_);
-    _exit(0);
-  }
-
- private:
-  const base::TimeDelta duration_;
-  DISALLOW_COPY_AND_ASSIGN(WaitAndExitDelegate);
-};
-
-bool CreateWaitAndExitThread(base::TimeDelta duration) {
-  scoped_ptr<WaitAndExitDelegate> delegate(new WaitAndExitDelegate(duration));
-
-  const bool thread_created =
-      base::PlatformThread::CreateNonJoinable(0, delegate.get());
-  if (!thread_created)
-    return false;
-
-  // A non joinable thread has been created. The thread will either terminate
-  // the process or will be terminated by the process. Therefore, keep the
-  // delegate object alive for the lifetime of the process.
-  WaitAndExitDelegate* leaking_delegate = delegate.release();
-  ANNOTATE_LEAKING_OBJECT_PTR(leaking_delegate);
-  ignore_result(leaking_delegate);
-  return true;
-}
-#endif
-
-class SuicideOnChannelErrorFilter : public IPC::MessageFilter {
- public:
-  // IPC::MessageFilter
-  void OnChannelError() override {
-    // For renderer/worker processes:
-    // On POSIX, at least, one can install an unload handler which loops
-    // forever and leave behind a renderer process which eats 100% CPU forever.
-    //
-    // This is because the terminate signals (ViewMsg_ShouldClose and the error
-    // from the IPC sender) are routed to the main message loop but never
-    // processed (because that message loop is stuck in V8).
-    //
-    // One could make the browser SIGKILL the renderers, but that leaves open a
-    // large window where a browser failure (or a user, manually terminating
-    // the browser because "it's stuck") will leave behind a process eating all
-    // the CPU.
-    //
-    // So, we install a filter on the sender so that we can process this event
-    // here and kill the process.
-    // TODO(earthdok): Re-enable on CrOS http://crbug.com/360622
-#if (defined(ADDRESS_SANITIZER) || defined(LEAK_SANITIZER) || \
-     defined(MEMORY_SANITIZER) || defined(THREAD_SANITIZER) || \
-     defined(UNDEFINED_SANITIZER)) && !defined(OS_CHROMEOS)
-    // Some sanitizer tools rely on exit handlers (e.g. to run leak detection,
-    // or dump code coverage data to disk). Instead of exiting the process
-    // immediately, we give it 60 seconds to run exit handlers.
-    CHECK(CreateWaitAndExitThread(base::TimeDelta::FromSeconds(60)));
-#if defined(LEAK_SANITIZER)
-    // Invoke LeakSanitizer early to avoid detecting shutdown-only leaks. If
-    // leaks are found, the process will exit here.
-    __lsan_do_leak_check();
-#endif
-#else
-    _exit(0);
-#endif
-  }
-
- protected:
-  ~SuicideOnChannelErrorFilter() override {}
-};
-
-#endif  // OS(POSIX)
-
-#if defined(OS_ANDROID)
-ChildThread* g_child_thread = NULL;
-
-// A lock protects g_child_thread.
-base::LazyInstance<base::Lock> g_lazy_child_thread_lock =
-    LAZY_INSTANCE_INITIALIZER;
-
-// base::ConditionVariable has an explicit constructor that takes
-// a base::Lock pointer as parameter. The base::DefaultLazyInstanceTraits
-// doesn't handle the case. Thus, we need our own class here.
-struct CondVarLazyInstanceTraits {
-  static const bool kRegisterOnExit = true;
-#ifndef NDEBUG
-  static const bool kAllowedToAccessOnNonjoinableThread = false;
-#endif
-
-  static base::ConditionVariable* New(void* instance) {
-    return new (instance) base::ConditionVariable(
-        g_lazy_child_thread_lock.Pointer());
-  }
-  static void Delete(base::ConditionVariable* instance) {
-    instance->~ConditionVariable();
-  }
-};
-
-// A condition variable that synchronize threads initializing and waiting
-// for g_child_thread.
-base::LazyInstance<base::ConditionVariable, CondVarLazyInstanceTraits>
-    g_lazy_child_thread_cv = LAZY_INSTANCE_INITIALIZER;
-
-void QuitMainThreadMessageLoop() {
-  base::MessageLoop::current()->Quit();
-}
-
-#endif
-
-}  // namespace
-
-ChildThread::Options::Options()
-    : channel_name(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-          switches::kProcessChannelID)),
-      use_mojo_channel(false),
-      in_browser_process(false) {
-}
-
-ChildThread::Options::Options(bool mojo)
-    : channel_name(base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-          switches::kProcessChannelID)),
-      use_mojo_channel(mojo),
-      in_browser_process(true) {
-}
-
-ChildThread::Options::Options(std::string name, bool mojo)
-    : channel_name(name), use_mojo_channel(mojo), in_browser_process(true) {
-}
-
-ChildThread::Options::~Options() {
-}
-
-ChildThread::ChildThreadMessageRouter::ChildThreadMessageRouter(
-    IPC::Sender* sender)
-    : sender_(sender) {}
-
-bool ChildThread::ChildThreadMessageRouter::Send(IPC::Message* msg) {
-  return sender_->Send(msg);
-}
-
-ChildThread::ChildThread()
-    : router_(this),
-      in_browser_process_(false),
-      channel_connected_factory_(this) {
-  Init(Options());
-}
-
-ChildThread::ChildThread(const Options& options)
-    : router_(this),
-      in_browser_process_(options.in_browser_process),
-      channel_connected_factory_(this) {
-  Init(options);
-}
-
-void ChildThread::ConnectChannel(bool use_mojo_channel) {
-  bool create_pipe_now = true;
-  if (use_mojo_channel) {
-    VLOG(1) << "Mojo is enabled on child";
-    channel_->Init(IPC::ChannelMojo::CreateClientFactory(channel_name_),
-                   create_pipe_now);
-    return;
-  }
-
-  VLOG(1) << "Mojo is disabled on child";
-  channel_->Init(channel_name_, IPC::Channel::MODE_CLIENT, create_pipe_now);
-}
-
-void ChildThread::Init(const Options& options) {
-  channel_name_ = options.channel_name;
-
-  g_lazy_tls.Pointer()->Set(this);
-  on_channel_error_called_ = false;
-  message_loop_ = base::MessageLoop::current();
-#ifdef IPC_MESSAGE_LOG_ENABLED
-  // We must make sure to instantiate the IPC Logger *before* we create the
-  // channel, otherwise we can get a callback on the IO thread which creates
-  // the logger, and the logger does not like being created on the IO thread.
-  IPC::Logging::GetInstance();
-#endif
-  channel_ = IPC::SyncChannel::Create(
-      this, ChildProcess::current()->io_message_loop_proxy(),
-      ChildProcess::current()->GetShutDownEvent());
-#ifdef IPC_MESSAGE_LOG_ENABLED
-  if (!in_browser_process_)
-    IPC::Logging::GetInstance()->SetIPCSender(this);
-#endif
-
-  mojo_application_.reset(new MojoApplication);
-
-  sync_message_filter_ =
-      new IPC::SyncMessageFilter(ChildProcess::current()->GetShutDownEvent());
-  thread_safe_sender_ = new ThreadSafeSender(
-      base::MessageLoopProxy::current().get(), sync_message_filter_.get());
-
-  resource_dispatcher_.reset(new ResourceDispatcher(
-      this, message_loop()->task_runner()));
-  websocket_dispatcher_.reset(new WebSocketDispatcher);
-  file_system_dispatcher_.reset(new FileSystemDispatcher());
-
-  histogram_message_filter_ = new ChildHistogramMessageFilter();
-  resource_message_filter_ =
-      new ChildResourceMessageFilter(resource_dispatcher());
-
-  service_worker_message_filter_ =
-      new ServiceWorkerMessageFilter(thread_safe_sender_.get());
-
-  quota_message_filter_ =
-      new QuotaMessageFilter(thread_safe_sender_.get());
-  quota_dispatcher_.reset(new QuotaDispatcher(thread_safe_sender_.get(),
-                                              quota_message_filter_.get()));
-  geofencing_message_filter_ =
-      new GeofencingMessageFilter(thread_safe_sender_.get());
-  bluetooth_message_filter_ =
-      new BluetoothMessageFilter(thread_safe_sender_.get());
-  notification_dispatcher_ =
-      new NotificationDispatcher(thread_safe_sender_.get());
-  push_dispatcher_ = new PushDispatcher(thread_safe_sender_.get());
-  navigator_connect_dispatcher_ =
-      new NavigatorConnectDispatcher(thread_safe_sender_.get());
-
-  channel_->AddFilter(histogram_message_filter_.get());
-  channel_->AddFilter(sync_message_filter_.get());
-  channel_->AddFilter(resource_message_filter_.get());
-  channel_->AddFilter(quota_message_filter_->GetFilter());
-  channel_->AddFilter(notification_dispatcher_->GetFilter());
-  channel_->AddFilter(push_dispatcher_->GetFilter());
-  channel_->AddFilter(service_worker_message_filter_->GetFilter());
-  channel_->AddFilter(geofencing_message_filter_->GetFilter());
-  channel_->AddFilter(bluetooth_message_filter_->GetFilter());
-  channel_->AddFilter(navigator_connect_dispatcher_->GetFilter());
-
-  if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSingleProcess)) {
-    // In single process mode, browser-side tracing will cover the whole
-    // process including renderers.
-    channel_->AddFilter(new tracing::ChildTraceMessageFilter(
-        ChildProcess::current()->io_message_loop_proxy()));
-  }
-
-  // In single process mode we may already have a power monitor
-  if (!base::PowerMonitor::Get()) {
-    scoped_ptr<PowerMonitorBroadcastSource> power_monitor_source(
-      new PowerMonitorBroadcastSource());
-    channel_->AddFilter(power_monitor_source->GetMessageFilter());
-
-    power_monitor_.reset(new base::PowerMonitor(
-        power_monitor_source.Pass()));
-  }
-
-#if defined(OS_POSIX)
-  // Check that --process-type is specified so we don't do this in unit tests
-  // and single-process mode.
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kProcessType))
-    channel_->AddFilter(new SuicideOnChannelErrorFilter());
-#endif
-
-  // Add filters passed here via options.
-  for (auto startup_filter : options.startup_filters) {
-    channel_->AddFilter(startup_filter);
-  }
-
-  ConnectChannel(options.use_mojo_channel);
-
-  int connection_timeout = kConnectionTimeoutS;
-  std::string connection_override =
-      base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
-          switches::kIPCConnectionTimeout);
-  if (!connection_override.empty()) {
-    int temp;
-    if (base::StringToInt(connection_override, &temp))
-      connection_timeout = temp;
-  }
-
-  base::MessageLoop::current()->PostDelayedTask(
-      FROM_HERE,
-      base::Bind(&ChildThread::EnsureConnected,
-                 channel_connected_factory_.GetWeakPtr()),
-      base::TimeDelta::FromSeconds(connection_timeout));
-
-#if defined(OS_ANDROID)
-  {
-    base::AutoLock lock(g_lazy_child_thread_lock.Get());
-    g_child_thread = this;
-  }
-  // Signalling without locking is fine here because only
-  // one thread can wait on the condition variable.
-  g_lazy_child_thread_cv.Get().Signal();
-#endif
-
-#if defined(TCMALLOC_TRACE_MEMORY_SUPPORTED)
-  trace_memory_controller_.reset(new base::debug::TraceMemoryController(
-      message_loop_->message_loop_proxy(),
-      ::HeapProfilerWithPseudoStackStart,
-      ::HeapProfilerStop,
-      ::GetHeapProfile));
-#endif
-
-  shared_bitmap_manager_.reset(
-      new ChildSharedBitmapManager(thread_safe_sender()));
-
-  gpu_memory_buffer_manager_.reset(
-      new ChildGpuMemoryBufferManager(thread_safe_sender()));
-
-  discardable_shared_memory_manager_.reset(
-      new ChildDiscardableSharedMemoryManager(thread_safe_sender()));
-}
-
-ChildThread::~ChildThread() {
-#ifdef IPC_MESSAGE_LOG_ENABLED
-  IPC::Logging::GetInstance()->SetIPCSender(NULL);
-#endif
-
-  channel_->RemoveFilter(histogram_message_filter_.get());
-  channel_->RemoveFilter(sync_message_filter_.get());
-
-  // The ChannelProxy object caches a pointer to the IPC thread, so need to
-  // reset it as it's not guaranteed to outlive this object.
-  // NOTE: this also has the side-effect of not closing the main IPC channel to
-  // the browser process.  This is needed because this is the signal that the
-  // browser uses to know that this process has died, so we need it to be alive
-  // until this process is shut down, and the OS closes the handle
-  // automatically.  We used to watch the object handle on Windows to do this,
-  // but it wasn't possible to do so on POSIX.
-  channel_->ClearIPCTaskRunner();
-  g_lazy_tls.Pointer()->Set(NULL);
-}
-
-void ChildThread::Shutdown() {
-  // Delete objects that hold references to blink so derived classes can
-  // safely shutdown blink in their Shutdown implementation.
-  file_system_dispatcher_.reset();
-  quota_dispatcher_.reset();
-  WebFileSystemImpl::DeleteThreadSpecificInstance();
-}
-
-void ChildThread::OnChannelConnected(int32 peer_pid) {
-  channel_connected_factory_.InvalidateWeakPtrs();
-}
-
-void ChildThread::OnChannelError() {
-  set_on_channel_error_called(true);
-  base::MessageLoop::current()->Quit();
-}
-
-bool ChildThread::Send(IPC::Message* msg) {
-  DCHECK(base::MessageLoop::current() == message_loop());
-  if (!channel_) {
-    delete msg;
-    return false;
-  }
-
-  return channel_->Send(msg);
-}
-
-MessageRouter* ChildThread::GetRouter() {
-  DCHECK(base::MessageLoop::current() == message_loop());
-  return &router_;
-}
-
-scoped_ptr<base::SharedMemory> ChildThread::AllocateSharedMemory(
-    size_t buf_size) {
-  DCHECK(base::MessageLoop::current() == message_loop());
-  return AllocateSharedMemory(buf_size, this);
-}
-
-// static
-scoped_ptr<base::SharedMemory> ChildThread::AllocateSharedMemory(
-    size_t buf_size,
-    IPC::Sender* sender) {
-  scoped_ptr<base::SharedMemory> shared_buf;
-#if defined(OS_WIN)
-  shared_buf.reset(new base::SharedMemory);
-  if (!shared_buf->CreateAnonymous(buf_size)) {
-    NOTREACHED();
-    return NULL;
-  }
-#else
-  // On POSIX, we need to ask the browser to create the shared memory for us,
-  // since this is blocked by the sandbox.
-  base::SharedMemoryHandle shared_mem_handle;
-  if (sender->Send(new ChildProcessHostMsg_SyncAllocateSharedMemory(
-                           buf_size, &shared_mem_handle))) {
-    if (base::SharedMemory::IsHandleValid(shared_mem_handle)) {
-      shared_buf.reset(new base::SharedMemory(shared_mem_handle, false));
-    } else {
-      NOTREACHED() << "Browser failed to allocate shared memory";
-      return NULL;
-    }
-  } else {
-    NOTREACHED() << "Browser allocation request message failed";
-    return NULL;
-  }
-#endif
-  return shared_buf;
-}
-
-bool ChildThread::OnMessageReceived(const IPC::Message& msg) {
-  if (mojo_application_->OnMessageReceived(msg))
-    return true;
-
-  // Resource responses are sent to the resource dispatcher.
-  if (resource_dispatcher_->OnMessageReceived(msg))
-    return true;
-  if (websocket_dispatcher_->OnMessageReceived(msg))
-    return true;
-  if (file_system_dispatcher_->OnMessageReceived(msg))
-    return true;
-
-  bool handled = true;
-  IPC_BEGIN_MESSAGE_MAP(ChildThread, msg)
-    IPC_MESSAGE_HANDLER(ChildProcessMsg_Shutdown, OnShutdown)
-#if defined(IPC_MESSAGE_LOG_ENABLED)
-    IPC_MESSAGE_HANDLER(ChildProcessMsg_SetIPCLoggingEnabled,
-                        OnSetIPCLoggingEnabled)
-#endif
-    IPC_MESSAGE_HANDLER(ChildProcessMsg_SetProfilerStatus,
-                        OnSetProfilerStatus)
-    IPC_MESSAGE_HANDLER(ChildProcessMsg_GetChildProfilerData,
-                        OnGetChildProfilerData)
-    IPC_MESSAGE_HANDLER(ChildProcessMsg_DumpHandles, OnDumpHandles)
-    IPC_MESSAGE_HANDLER(ChildProcessMsg_SetProcessBackgrounded,
-                        OnProcessBackgrounded)
-#if defined(USE_TCMALLOC)
-    IPC_MESSAGE_HANDLER(ChildProcessMsg_GetTcmallocStats, OnGetTcmallocStats)
-#endif
-    IPC_MESSAGE_UNHANDLED(handled = false)
-  IPC_END_MESSAGE_MAP()
-
-  if (handled)
-    return true;
-
-  if (msg.routing_id() == MSG_ROUTING_CONTROL)
-    return OnControlMessageReceived(msg);
-
-  return router_.OnMessageReceived(msg);
-}
-
-bool ChildThread::OnControlMessageReceived(const IPC::Message& msg) {
-  return false;
-}
-
-void ChildThread::OnShutdown() {
-  base::MessageLoop::current()->Quit();
-}
-
-#if defined(IPC_MESSAGE_LOG_ENABLED)
-void ChildThread::OnSetIPCLoggingEnabled(bool enable) {
-  if (enable)
-    IPC::Logging::GetInstance()->Enable();
-  else
-    IPC::Logging::GetInstance()->Disable();
-}
-#endif  //  IPC_MESSAGE_LOG_ENABLED
-
-void ChildThread::OnSetProfilerStatus(ThreadData::Status status) {
-  ThreadData::InitializeAndSetTrackingStatus(status);
-}
-
-void ChildThread::OnGetChildProfilerData(int sequence_number) {
-  tracked_objects::ProcessDataSnapshot process_data;
-  ThreadData::Snapshot(false, &process_data);
-
-  Send(new ChildProcessHostMsg_ChildProfilerData(sequence_number,
-                                                 process_data));
-}
-
-void ChildThread::OnDumpHandles() {
-#if defined(OS_WIN)
-  scoped_refptr<HandleEnumerator> handle_enum(
-      new HandleEnumerator(
-          base::CommandLine::ForCurrentProcess()->HasSwitch(
-              switches::kAuditAllHandles)));
-  handle_enum->EnumerateHandles();
-  Send(new ChildProcessHostMsg_DumpHandlesDone);
-#else
-  NOTIMPLEMENTED();
-#endif
-}
-
-#if defined(USE_TCMALLOC)
-void ChildThread::OnGetTcmallocStats() {
-  std::string result;
-  char buffer[1024 * 32];
-  base::allocator::GetStats(buffer, sizeof(buffer));
-  result.append(buffer);
-  Send(new ChildProcessHostMsg_TcmallocStats(result));
-}
-#endif
-
-ChildThread* ChildThread::current() {
-  return g_lazy_tls.Pointer()->Get();
-}
-
-#if defined(OS_ANDROID)
-// The method must NOT be called on the child thread itself.
-// It may block the child thread if so.
-void ChildThread::ShutdownThread() {
-  DCHECK(!ChildThread::current()) <<
-      "this method should NOT be called from child thread itself";
-  {
-    base::AutoLock lock(g_lazy_child_thread_lock.Get());
-    while (!g_child_thread)
-      g_lazy_child_thread_cv.Get().Wait();
-  }
-  DCHECK_NE(base::MessageLoop::current(), g_child_thread->message_loop());
-  g_child_thread->message_loop()->PostTask(
-      FROM_HERE, base::Bind(&QuitMainThreadMessageLoop));
-}
-#endif
-
-void ChildThread::OnProcessFinalRelease() {
-  if (on_channel_error_called_) {
-    base::MessageLoop::current()->Quit();
-    return;
-  }
-
-  // The child process shutdown sequence is a request response based mechanism,
-  // where we send out an initial feeler request to the child process host
-  // instance in the browser to verify if it's ok to shutdown the child process.
-  // The browser then sends back a response if it's ok to shutdown. This avoids
-  // race conditions if the process refcount is 0 but there's an IPC message
-  // inflight that would addref it.
-  Send(new ChildProcessHostMsg_ShutdownRequest);
-}
-
-void ChildThread::EnsureConnected() {
-  VLOG(0) << "ChildThread::EnsureConnected()";
-  base::KillProcess(base::GetCurrentProcessHandle(), 0, false);
-}
-
-void ChildThread::OnProcessBackgrounded(bool background) {
-  // Set timer slack to maximum on main thread when in background.
-  base::TimerSlack timer_slack = base::TIMER_SLACK_NONE;
-  if (background)
-    timer_slack = base::TIMER_SLACK_MAXIMUM;
-  base::MessageLoop::current()->SetTimerSlack(timer_slack);
-}
-
-}  // namespace content