Make utility process run in-process when running in single-process mode.

content/utility/utility_thread_impl.cc

Index: content/utility/utility_thread_impl.cc
===================================================================
--- content/utility/utility_thread_impl.cc	(revision 209067)
+++ content/utility/utility_thread_impl.cc	(working copy)
@@ -13,6 +13,7 @@
 #include "content/child/webkitplatformsupport_impl.h"
 #include "content/common/child_process_messages.h"
 #include "content/common/utility_messages.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/utility/content_utility_client.h"
 #include "third_party/WebKit/public/web/WebKit.h"
 #include "webkit/plugins/npapi/plugin_list.h"
@@ -36,19 +37,22 @@
 
 }  // namespace
 
-UtilityThreadImpl::UtilityThreadImpl()
-    : batch_mode_(false) {
-  ChildProcess::current()->AddRefProcess();
-  webkit_platform_support_.reset(new WebKitPlatformSupportImpl);
-  WebKit::initialize(webkit_platform_support_.get());
-  GetContentClient()->utility()->UtilityThreadStarted();
+UtilityThreadImpl::UtilityThreadImpl() : initialize_webkit_(true) {
+  Init();
 }
 
+UtilityThreadImpl::UtilityThreadImpl(const std::string& channel_name)
+    : ChildThread(channel_name),
+      initialize_webkit_(false) {
+  Init();
+}
+
 UtilityThreadImpl::~UtilityThreadImpl() {
 }
 
 void UtilityThreadImpl::Shutdown() {
-  WebKit::shutdown();
+  if (initialize_webkit_)
+    WebKit::shutdown();
 }
 
 bool UtilityThreadImpl::Send(IPC::Message* msg) {
@@ -56,8 +60,15 @@
 }
 
 void UtilityThreadImpl::ReleaseProcessIfNeeded() {
-  if (!batch_mode_)
-    ChildProcess::current()->ReleaseProcess();
+  if (batch_mode_)
+    return;
+
+  // We don't need to call ChildProcess::current()->ReleaseProcess() here, and
+  // can just quit the message loop directly. This is because the unlike other
+  // kind of child processes, there's no race condition between killing utility
+  // processes. A side benefit is that it makes tests which use this code path
+  // easier to clean up.
+  base::MessageLoop::current()->Quit();
 }
 
 #if defined(OS_WIN)
@@ -72,6 +83,19 @@
 
 #endif  // OS_WIN
 
+void UtilityThreadImpl::Init() {
+  batch_mode_ = false;
+  ChildProcess::current()->AddRefProcess();
+  if (initialize_webkit_) {
+    // We can only initialize WebKit on one thread, and in single process mode
+    // we run the utility thread on separate thread. This means that if any code
+    // needs WebKit initialized in the utility process, they need to have
+    // another path to support single process mode.
+    webkit_platform_support_.reset(new WebKitPlatformSupportImpl);
+    WebKit::initialize(webkit_platform_support_.get());
+  }
+  GetContentClient()->utility()->UtilityThreadStarted();
+}
 
 bool UtilityThreadImpl::OnControlMessageReceived(const IPC::Message& msg) {
   if (GetContentClient()->utility()->OnMessageReceived(msg))