Simplify how Content*Client interfaces are created. Instead of depending on the embedder to know when to create and set them and to handle special cases like zygote/single-process, directly ask the embedder to create an instance of a specific type. Also, if the embedder doesn't return an instance create the empty version.

Remove MockContentRendererClient since it existed before ContentRendererClient had an implementation and has no need anymore. Rename MockContentBrowserClient to TestContentBrowserClient to better reflect how it's used.

BUG=98716
Review URL: https://chromiumcodereview.appspot.com/10479023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@140524 0039d316-1c4b-4281-b951-d872f2087c98

43 files changed, 260 insertions, 588 deletions

diff --git a/ash/shell/content_client/shell_main_delegate.cc b/ash/shell/content_client/shell_main_delegate.cc
index 3257ae2..343ba27 100644
--- a/ash/shell/content_client/shell_main_delegate.cc
+++ b/ash/shell/content_client/shell_main_delegate.cc
@@ -9,9 +9,6 @@
 #include "base/file_path.h"
 #include "base/path_service.h"
 #include "content/public/common/content_switches.h"
-#include "content/shell/shell_content_plugin_client.h"
-#include "content/shell/shell_content_renderer_client.h"
-#include "content/shell/shell_content_utility_client.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
 
@@ -30,7 +27,6 @@ bool ShellMainDelegate::BasicStartupComplete(int* exit_code) {
       command_line.GetSwitchValueASCII(switches::kProcessType);
 
   content::SetContentClient(&content_client_);
-  InitializeShellContentClient(process_type);
 
   return false;
 }
@@ -39,31 +35,9 @@ void ShellMainDelegate::PreSandboxStartup() {
   InitializeResourceBundle();
 }
 
-#if defined(OS_POSIX)
-
-void ShellMainDelegate::ZygoteForked() {
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  std::string process_type =
-      command_line.GetSwitchValueASCII(switches::kProcessType);
-  InitializeShellContentClient(process_type);
-}
-#endif
-
-void ShellMainDelegate::InitializeShellContentClient(
-    const std::string& process_type) {
-  if (process_type.empty()) {
-    browser_client_.reset(new ShellContentBrowserClient);
-    content::GetContentClient()->set_browser(browser_client_.get());
-  } else if (process_type == switches::kRendererProcess) {
-    renderer_client_.reset(new content::ShellContentRendererClient);
-    content::GetContentClient()->set_renderer(renderer_client_.get());
-  } else if (process_type == switches::kPluginProcess) {
-    plugin_client_.reset(new content::ShellContentPluginClient);
-    content::GetContentClient()->set_plugin(plugin_client_.get());
-  } else if (process_type == switches::kUtilityProcess) {
-    utility_client_.reset(new content::ShellContentUtilityClient);
-    content::GetContentClient()->set_utility(utility_client_.get());
-  }
+content::ContentBrowserClient* ShellMainDelegate::CreateContentBrowserClient() {
+  browser_client_.reset(new ShellContentBrowserClient);
+  return browser_client_.get();
 }
 
 void ShellMainDelegate::InitializeResourceBundle() {
diff --git a/ash/shell/content_client/shell_main_delegate.h b/ash/shell/content_client/shell_main_delegate.h
index 54cc24f..0d297b6 100644
--- a/ash/shell/content_client/shell_main_delegate.h
+++ b/ash/shell/content_client/shell_main_delegate.h
@@ -29,18 +29,12 @@ class ShellMainDelegate : public content::ContentMainDelegate {
 
   virtual bool BasicStartupComplete(int* exit_code) OVERRIDE;
   virtual void PreSandboxStartup() OVERRIDE;
-#if defined(OS_POSIX)
-  virtual void ZygoteForked() OVERRIDE;
-#endif  // OS_MACOSX
+  virtual content::ContentBrowserClient* CreateContentBrowserClient() OVERRIDE;
 
  private:
-  void InitializeShellContentClient(const std::string& process_type);
   void InitializeResourceBundle();
 
   scoped_ptr<ShellContentBrowserClient> browser_client_;
-  scoped_ptr<content::ShellContentRendererClient> renderer_client_;
-  scoped_ptr<content::ShellContentPluginClient> plugin_client_;
-  scoped_ptr<content::ShellContentUtilityClient> utility_client_;
   content::ShellContentClient content_client_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellMainDelegate);
diff --git a/chrome/app/chrome_main_delegate.cc b/chrome/app/chrome_main_delegate.cc
index e00b553..ab0729b1 100644
--- a/chrome/app/chrome_main_delegate.cc
+++ b/chrome/app/chrome_main_delegate.cc
@@ -255,26 +255,6 @@ void EnableHeapProfiler(const CommandLine& command_line) {
 #endif
 }
 
-void InitializeChromeContentRendererClient() {
-  content::GetContentClient()->set_renderer(
-      &g_chrome_content_renderer_client.Get());
-}
-
-void InitializeChromeContentClient(const std::string& process_type) {
-  if (process_type.empty()) {
-    content::GetContentClient()->set_browser(
-        &g_chrome_content_browser_client.Get());
-  } else if (process_type == switches::kPluginProcess) {
-    content::GetContentClient()->set_plugin(
-        &g_chrome_content_plugin_client.Get());
-  } else if (process_type == switches::kRendererProcess) {
-    InitializeChromeContentRendererClient();
-  } else if (process_type == switches::kUtilityProcess) {
-    content::GetContentClient()->set_utility(
-        &g_chrome_content_utility_client.Get());
-  }
-}
-
 // Returns true if this subprocess type needs the ResourceBundle initialized
 // and resources loaded.
 bool SubprocessNeedsResourceBundle(const std::string& process_type) {
@@ -447,10 +427,7 @@ bool ChromeMainDelegate::BasicStartupComplete(int* exit_code) {
     base::FieldTrial::EnableBenchmarking();
   }
 
-  std::string process_type =  command_line.GetSwitchValueASCII(
-      switches::kProcessType);
   content::SetContentClient(&chrome_content_client_);
-  InitializeChromeContentClient(process_type);
 
   return false;
 }
@@ -584,9 +561,6 @@ void ChromeMainDelegate::PreSandboxStartup() {
   if (command_line.HasSwitch(switches::kMessageLoopHistogrammer))
     MessageLoop::EnableHistogrammer(true);
 
-  if (command_line.HasSwitch(switches::kSingleProcess))
-    InitializeChromeContentRendererClient();
-
   logging::OldFileDeletionState file_state =
       logging::APPEND_TO_OLD_LOG_FILE;
   if (process_type.empty()) {
@@ -716,10 +690,6 @@ content::ZygoteForkDelegate* ChromeMainDelegate::ZygoteStarting() {
 }
 
 void ChromeMainDelegate::ZygoteForked() {
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  std::string process_type =
-      command_line.GetSwitchValueASCII(switches::kProcessType);
-
   Profiling::ProcessStarted();
   if (Profiling::BeingProfiled()) {
     base::debug::RestartProfilingAfterFork();
@@ -731,7 +701,25 @@ void ChromeMainDelegate::ZygoteForked() {
   // this up for the browser process in a different manner.
   InitCrashReporter();
 #endif
-
-  InitializeChromeContentClient(process_type);
 }
+
 #endif  // OS_MACOSX
+
+content::ContentBrowserClient*
+    ChromeMainDelegate::CreateContentBrowserClient() {
+  return &g_chrome_content_browser_client.Get();
+}
+
+content::ContentPluginClient* ChromeMainDelegate::CreateContentPluginClient() {
+  return &g_chrome_content_plugin_client.Get();
+}
+
+content::ContentRendererClient*
+    ChromeMainDelegate::CreateContentRendererClient() {
+  return &g_chrome_content_renderer_client.Get();
+}
+
+content::ContentUtilityClient*
+    ChromeMainDelegate::CreateContentUtilityClient() {
+  return &g_chrome_content_utility_client.Get();
+}
diff --git a/chrome/app/chrome_main_delegate.h b/chrome/app/chrome_main_delegate.h
index 3e9b72a..faa1920 100644
--- a/chrome/app/chrome_main_delegate.h
+++ b/chrome/app/chrome_main_delegate.h
@@ -17,20 +17,15 @@ class ChromeMainDelegate : public content::ContentMainDelegate {
   ChromeMainDelegate();
   virtual ~ChromeMainDelegate();
 
+ private:
+  // content::ContentMainDelegate implementation:
   virtual bool BasicStartupComplete(int* exit_code) OVERRIDE;
-
-#if defined(OS_MACOSX)
-  void InitMacCrashReporter(const CommandLine& command_line,
-                            const std::string& process_type);
-#endif  // defined(OS_MACOSX)
-
   virtual void PreSandboxStartup() OVERRIDE;
   virtual void SandboxInitialized(const std::string& process_type) OVERRIDE;
   virtual int RunProcess(
       const std::string& process_type,
       const content::MainFunctionParams& main_function_params) OVERRIDE;
   virtual void ProcessExiting(const std::string& process_type) OVERRIDE;
-
 #if defined(OS_MACOSX)
   virtual bool ProcessRegistersWithSystemProcess(
       const std::string& process_type) OVERRIDE;
@@ -41,8 +36,17 @@ class ChromeMainDelegate : public content::ContentMainDelegate {
   virtual content::ZygoteForkDelegate* ZygoteStarting() OVERRIDE;
   virtual void ZygoteForked() OVERRIDE;
 #endif
+  virtual content::ContentBrowserClient* CreateContentBrowserClient() OVERRIDE;
+  virtual content::ContentPluginClient* CreateContentPluginClient() OVERRIDE;
+  virtual content::ContentRendererClient*
+      CreateContentRendererClient() OVERRIDE;
+  virtual content::ContentUtilityClient* CreateContentUtilityClient() OVERRIDE;
+
+#if defined(OS_MACOSX)
+  void InitMacCrashReporter(const CommandLine& command_line,
+                            const std::string& process_type);
+#endif  // defined(OS_MACOSX)
 
- private:
   chrome::ChromeContentClient chrome_content_client_;
   scoped_ptr<base::StatsScope<base::StatsCounterTimer> > startup_timer_;
 
diff --git a/chrome/test/base/chrome_render_view_test.cc b/chrome/test/base/chrome_render_view_test.cc
index 15f91e7..80901c2 100644
--- a/chrome/test/base/chrome_render_view_test.cc
+++ b/chrome/test/base/chrome_render_view_test.cc
@@ -51,7 +51,8 @@ ChromeRenderViewTest::~ChromeRenderViewTest() {
 }
 
 void ChromeRenderViewTest::SetUp() {
-  content::GetContentClient()->set_renderer(&chrome_content_renderer_client_);
+  content::GetContentClient()->set_renderer_for_testing(
+      &chrome_content_renderer_client_);
   extension_dispatcher_ = new ExtensionDispatcher();
   chrome_content_renderer_client_.SetExtensionDispatcher(extension_dispatcher_);
 
diff --git a/chrome/test/base/chrome_test_suite.cc b/chrome/test/base/chrome_test_suite.cc
index cdda117..d66eec5 100644
--- a/chrome/test/base/chrome_test_suite.cc
+++ b/chrome/test/base/chrome_test_suite.cc
@@ -105,7 +105,7 @@ class ChromeTestSuiteInitializer : public testing::EmptyTestEventListener {
     DCHECK(!content::GetContentClient());
     content_client_.reset(new chrome::ChromeContentClient);
     browser_content_client_.reset(new chrome::ChromeContentBrowserClient());
-    content_client_->set_browser(browser_content_client_.get());
+    content_client_->set_browser_for_testing(browser_content_client_.get());
     content::SetContentClient(content_client_.get());
 
     SetUpHostResolver();
diff --git a/chrome/test/base/in_process_browser_test.cc b/chrome/test/base/in_process_browser_test.cc
index 3042514..b490213 100644
--- a/chrome/test/base/in_process_browser_test.cc
+++ b/chrome/test/base/in_process_browser_test.cc
@@ -28,6 +28,7 @@
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/logging_chrome.h"
 #include "chrome/common/url_constants.h"
+#include "chrome/renderer/chrome_content_renderer_client.h"
 #include "chrome/test/base/chrome_test_suite.h"
 #include "chrome/test/base/test_launcher_utils.h"
 #include "chrome/test/base/testing_browser_process.h"
@@ -37,7 +38,6 @@
 #include "content/public/browser/render_process_host.h"
 #include "content/public/test/test_browser_thread.h"
 #include "content/public/test/test_launcher.h"
-#include "content/renderer/mock_content_renderer_client.h"
 #include "net/base/mock_host_resolver.h"
 #include "net/test/test_server.h"
 #include "ui/compositor/compositor_switches.h"
@@ -114,8 +114,8 @@ void InProcessBrowserTest::SetUp() {
   if (command_line->HasSwitch(switches::kSingleProcess)) {
     content::RenderProcessHost::set_run_renderer_in_process(true);
     single_process_renderer_client_.reset(
-        new content::MockContentRendererClient);
-    content::GetContentClient()->set_renderer(
+        new chrome::ChromeContentRendererClient);
+    content::GetContentClient()->set_renderer_for_testing(
         single_process_renderer_client_.get());
   }
 
diff --git a/chrome_frame/test/net/fake_external_tab.cc b/chrome_frame/test/net/fake_external_tab.cc
index d73d03d..203fa1f 100644
--- a/chrome_frame/test/net/fake_external_tab.cc
+++ b/chrome_frame/test/net/fake_external_tab.cc
@@ -147,17 +147,19 @@ class FakeMainDelegate : public content::ContentMainDelegate {
     logging_win::InstallTestLogCollector(
         testing::UnitTest::GetInstance());
 
-    // Initialize the content client.
     content::SetContentClient(&g_chrome_content_client.Get());
-
-    // Override the default ContentBrowserClient to let Chrome participate in
-    // content logic.  We use a subclass of Chrome's implementation,
-    // FakeContentBrowserClient, to override CreateBrowserMainParts.  Must
-    // be done before any tabs are created.
-    content::GetContentClient()->set_browser(&g_browser_client.Get());
-    content::GetContentClient()->set_renderer(&g_renderer_client.Get());
+    content::GetContentClient()->set_renderer_for_testing(
+        &g_renderer_client.Get());
     return false;
   }
+
+  // Override the default ContentBrowserClient to let Chrome participate in
+  // content logic.  We use a subclass of Chrome's implementation,
+  // FakeContentBrowserClient, to override CreateBrowserMainParts.  Must
+  // be done before any tabs are created.
+  virtual content::ContentBrowserClient* CreateContentBrowserClient() OVERRIDE {
+    return &g_browser_client.Get();
+  };
 };
 
 void FilterDisabledTests() {
diff --git a/content/app/content_main_runner.cc b/content/app/content_main_runner.cc
index 02eacd2..646becc 100644
--- a/content/app/content_main_runner.cc
+++ b/content/app/content_main_runner.cc
@@ -11,6 +11,7 @@
 #include "base/debug/trace_event.h"
 #include "base/file_path.h"
 #include "base/i18n/icu_util.h"
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/metrics/stats_table.h"
@@ -23,12 +24,16 @@
 #include "content/common/url_schemes.h"
 #include "content/public/app/content_main_delegate.h"
 #include "content/public/app/startup_helper_win.h"
+#include "content/public/browser/content_browser_client.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_constants.h"
 #include "content/public/common/content_paths.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "content/public/common/sandbox_init.h"
+#include "content/public/plugin/content_plugin_client.h"
+#include "content/public/renderer/content_renderer_client.h"
+#include "content/public/utility/content_utility_client.h"
 #include "crypto/nss_util.h"
 #include "ipc/ipc_switches.h"
 #include "media/base/media.h"
@@ -81,12 +86,21 @@ extern int WorkerMain(const content::MainFunctionParams&);
 extern int UtilityMain(const content::MainFunctionParams&);
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
 namespace content {
-extern int ZygoteMain(const content::MainFunctionParams&,
-                      content::ZygoteForkDelegate* forkdelegate);
+extern int ZygoteMain(const MainFunctionParams&,
+                      ZygoteForkDelegate* forkdelegate);
 }  // namespace content
 #endif
 
-namespace {
+namespace content {
+
+base::LazyInstance<ContentBrowserClient>
+    g_empty_content_browser_client = LAZY_INSTANCE_INITIALIZER;
+base::LazyInstance<ContentPluginClient>
+    g_empty_content_plugin_client = LAZY_INSTANCE_INITIALIZER;
+base::LazyInstance<ContentRendererClient>
+    g_empty_content_renderer_client = LAZY_INSTANCE_INITIALIZER;
+base::LazyInstance<ContentUtilityClient>
+    g_empty_content_utility_client = LAZY_INSTANCE_INITIALIZER;
 
 #if defined(OS_WIN)
 
@@ -206,20 +220,50 @@ static void InitializeStatsTable(const CommandLine& command_line) {
     // NOTIMPLEMENTED: we probably need to shut this down correctly to avoid
     // leaking shared memory regions on posix platforms.
     std::string statsfile =
-      base::StringPrintf(
-          "%s-%u", content::kStatsFilename,
+      base::StringPrintf("%s-%u", kStatsFilename,
           static_cast<unsigned int>(GetBrowserPid(command_line)));
     base::StatsTable* stats_table = new base::StatsTable(statsfile,
-        content::kStatsMaxThreads, content::kStatsMaxCounters);
+        kStatsMaxThreads, kStatsMaxCounters);
     base::StatsTable::set_current(stats_table);
   }
 }
 
+class ContentClientInitializer {
+ public:
+  static void Set(const std::string& process_type,
+                  ContentMainDelegate* delegate) {
+    ContentClient* content_client = GetContentClient();
+    if (process_type.empty()) {
+      if (delegate)
+        content_client->browser_ = delegate->CreateContentBrowserClient();
+      if (!content_client->browser_)
+        content_client->browser_ = &g_empty_content_browser_client.Get();
+    }
+
+    if (process_type == switches::kPluginProcess) {
+      if (delegate)
+        content_client->plugin_ = delegate->CreateContentPluginClient();
+      if (!content_client->plugin_)
+        content_client->plugin_ = &g_empty_content_plugin_client.Get();
+    } else if (process_type == switches::kRendererProcess) {
+      if (delegate)
+        content_client->renderer_ = delegate->CreateContentRendererClient();
+      if (!content_client->renderer_)
+        content_client->renderer_ = &g_empty_content_renderer_client.Get();
+    } else if (process_type == switches::kUtilityProcess) {
+      if (delegate)
+        content_client->utility_ = delegate->CreateContentUtilityClient();
+      if (!content_client->utility_)
+        content_client->utility_ = &g_empty_content_utility_client.Get();
+    }
+  }
+};
+
 // We dispatch to a process-type-specific FooMain() based on a command-line
 // flag.  This struct is used to build a table of (flag, main function) pairs.
 struct MainFunction {
   const char* name;
-  int (*function)(const content::MainFunctionParams&);
+  int (*function)(const MainFunctionParams&);
 };
 
 #if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
@@ -227,8 +271,8 @@ struct MainFunction {
 // subprocesses that are launched via the zygote.  This function
 // fills in some process-launching bits around ZygoteMain().
 // Returns the exit code of the subprocess.
-int RunZygote(const content::MainFunctionParams& main_function_params,
-              content::ContentMainDelegate* delegate) {
+int RunZygote(const MainFunctionParams& main_function_params,
+              ContentMainDelegate* delegate) {
   static const MainFunction kMainFunctions[] = {
     { switches::kRendererProcess,    RendererMain },
     { switches::kWorkerProcess,      WorkerMain },
@@ -236,19 +280,19 @@ int RunZygote(const content::MainFunctionParams& main_function_params,
     { switches::kUtilityProcess,     UtilityMain },
   };
 
-  scoped_ptr<content::ZygoteForkDelegate> zygote_fork_delegate;
+  scoped_ptr<ZygoteForkDelegate> zygote_fork_delegate;
   if (delegate) {
     zygote_fork_delegate.reset(delegate->ZygoteStarting());
     // Each Renderer we spawn will re-attempt initialization of the media
     // libraries, at which point failure will be detected and handled, so
     // we do not need to cope with initialization failures here.
     FilePath media_path;
-    if (PathService::Get(content::DIR_MEDIA_LIBS, &media_path))
+    if (PathService::Get(DIR_MEDIA_LIBS, &media_path))
       media::InitializeMediaLibrary(media_path);
   }
 
   // This function call can return multiple times, once per fork().
-  if (!content::ZygoteMain(main_function_params, zygote_fork_delegate.get()))
+  if (!ZygoteMain(main_function_params, zygote_fork_delegate.get()))
     return 1;
 
   if (delegate) delegate->ZygoteForked();
@@ -256,6 +300,9 @@ int RunZygote(const content::MainFunctionParams& main_function_params,
   // Zygote::HandleForkRequest may have reallocated the command
   // line so update it here with the new version.
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+  std::string process_type =
+      command_line.GetSwitchValueASCII(switches::kProcessType);
+  ContentClientInitializer::Set(process_type, delegate);
 
   // If a custom user agent was passed on the command line, we need
   // to (re)set it now, rather than using the default one the zygote
@@ -270,11 +317,7 @@ int RunZygote(const content::MainFunctionParams& main_function_params,
   // within the new processes as well.
   InitializeStatsTable(command_line);
 
-  content::MainFunctionParams main_params(command_line);
-
-  // Get the new process type from the new command line.
-  std::string process_type =
-      command_line.GetSwitchValueASCII(switches::kProcessType);
+  MainFunctionParams main_params(command_line);
 
   for (size_t i = 0; i < arraysize(kMainFunctions); ++i) {
     if (process_type == kMainFunctions[i].name)
@@ -294,8 +337,8 @@ int RunZygote(const content::MainFunctionParams& main_function_params,
 // Returns the exit code for this process.
 int RunNamedProcessTypeMain(
     const std::string& process_type,
-    const content::MainFunctionParams& main_function_params,
-    content::ContentMainDelegate* delegate) {
+    const MainFunctionParams& main_function_params,
+    ContentMainDelegate* delegate) {
   static const MainFunction kMainFunctions[] = {
     { "",                            BrowserMain },
     { switches::kRendererProcess,    RendererMain },
@@ -334,7 +377,7 @@ int RunNamedProcessTypeMain(
   return 1;
 }
 
-class ContentMainRunnerImpl : public content::ContentMainRunner {
+class ContentMainRunnerImpl : public ContentMainRunner {
  public:
   ContentMainRunnerImpl()
       : is_initialized_(false),
@@ -361,12 +404,12 @@ static void ReleaseFreeMemoryThunk() {
 #if defined(OS_WIN)
   virtual int Initialize(HINSTANCE instance,
                          sandbox::SandboxInterfaceInfo* sandbox_info,
-                         content::ContentMainDelegate* delegate) OVERRIDE {
+                         ContentMainDelegate* delegate) OVERRIDE {
     // argc/argv are ignored on Windows; see command_line.h for details.
     int argc = 0;
     char** argv = NULL;
 
-    content::RegisterInvalidParamHandler();
+    RegisterInvalidParamHandler();
     _Module.Init(NULL, static_cast<HINSTANCE>(instance));
 
     if (sandbox_info)
@@ -377,7 +420,7 @@ static void ReleaseFreeMemoryThunk() {
 #else  // !OS_WIN
   virtual int Initialize(int argc,
                          const char** argv,
-                         content::ContentMainDelegate* delegate) OVERRIDE {
+                         ContentMainDelegate* delegate) OVERRIDE {
 
     // NOTE(willchan): One might ask why this call is done here rather than in
     // process_util_linux.cc with the definition of
@@ -448,14 +491,16 @@ static void ReleaseFreeMemoryThunk() {
     int exit_code;
     if (delegate && delegate->BasicStartupComplete(&exit_code))
       return exit_code;
-    DCHECK(!delegate || content::GetContentClient()) <<
-        "BasicStartupComplete didn't set the content client";
 
     completed_basic_startup_ = true;
 
     const CommandLine& command_line = *CommandLine::ForCurrentProcess();
     std::string process_type =
-          command_line.GetSwitchValueASCII(switches::kProcessType);
+        command_line.GetSwitchValueASCII(switches::kProcessType);
+
+    if (!GetContentClient())
+      SetContentClient(&empty_content_client_);
+    ContentClientInitializer::Set(process_type, delegate_);
 
     // Enable startup tracing asap to avoid early TRACE_EVENT calls being
     // ignored.
@@ -487,7 +532,7 @@ static void ReleaseFreeMemoryThunk() {
 #if defined(ENABLE_HIDPI)
     ui::EnableHighDPISupport();
 #endif
-    content::SetupCRT(command_line);
+    SetupCRT(command_line);
 #endif
 
 #if defined(OS_POSIX)
@@ -513,8 +558,8 @@ static void ReleaseFreeMemoryThunk() {
 #endif
 
     ui::RegisterPathProvider();
-    content::RegisterPathProvider();
-    content::RegisterContentSchemes(true);
+    RegisterPathProvider();
+    RegisterContentSchemes(true);
 
     CHECK(icu_util::Initialize());
 
@@ -535,7 +580,7 @@ static void ReleaseFreeMemoryThunk() {
       CommonSubprocessInit(process_type);
 
 #if defined(OS_WIN)
-    CHECK(content::InitializeSandbox(sandbox_info));
+    CHECK(InitializeSandbox(sandbox_info));
 #elif defined(OS_MACOSX)
     if (process_type == switches::kRendererProcess ||
         process_type == switches::kPpapiPluginProcess ||
@@ -543,7 +588,7 @@ static void ReleaseFreeMemoryThunk() {
       // On OS X the renderer sandbox needs to be initialized later in the
       // startup sequence in RendererMainPlatformDelegate::EnableSandbox().
     } else {
-      CHECK(content::InitializeSandbox());
+      CHECK(InitializeSandbox());
     }
 #endif
 
@@ -565,7 +610,7 @@ static void ReleaseFreeMemoryThunk() {
     std::string process_type =
           command_line.GetSwitchValueASCII(switches::kProcessType);
 
-    content::MainFunctionParams main_params(command_line);
+    MainFunctionParams main_params(command_line);
 #if defined(OS_WIN)
     main_params.sandbox_info = &sandbox_info_;
 #elif defined(OS_MACOSX)
@@ -605,7 +650,7 @@ static void ReleaseFreeMemoryThunk() {
     is_shutdown_ = true;
   }
 
- protected:
+ private:
   // True if the runner has been initialized.
   bool is_initialized_;
 
@@ -615,8 +660,11 @@ static void ReleaseFreeMemoryThunk() {
   // True if basic startup was completed.
   bool completed_basic_startup_;
 
+  // Used if the embedder doesn't set one.
+  ContentClient empty_content_client_;
+
   // The delegate will outlive this object.
-  content::ContentMainDelegate* delegate_;
+  ContentMainDelegate* delegate_;
 
   scoped_ptr<base::AtExitManager> exit_manager_;
 #if defined(OS_WIN)
@@ -628,10 +676,6 @@ static void ReleaseFreeMemoryThunk() {
   DISALLOW_COPY_AND_ASSIGN(ContentMainRunnerImpl);
 };
 
-}  // namespace
-
-namespace content {
-
 // static
 ContentMainRunner* ContentMainRunner::Create() {
   return new ContentMainRunnerImpl();
diff --git a/content/browser/child_process_security_policy_unittest.cc b/content/browser/child_process_security_policy_unittest.cc
index 39d50d3..77be482 100644
--- a/content/browser/child_process_security_policy_unittest.cc
+++ b/content/browser/child_process_security_policy_unittest.cc
@@ -9,9 +9,9 @@
 #include "base/file_path.h"
 #include "base/platform_file.h"
 #include "content/browser/child_process_security_policy_impl.h"
-#include "content/browser/mock_content_browser_client.h"
 #include "content/common/test_url_constants.h"
 #include "content/public/common/url_constants.h"
+#include "content/test/test_content_browser_client.h"
 #include "googleurl/src/gurl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -21,7 +21,7 @@ const int kRendererID = 42;
 const int kWorkerRendererID = kRendererID + 1;
 
 class ChildProcessSecurityPolicyTestBrowserClient
-    : public content::MockContentBrowserClient {
+    : public content::TestContentBrowserClient {
  public:
   ChildProcessSecurityPolicyTestBrowserClient() {}
 
@@ -50,7 +50,7 @@ class ChildProcessSecurityPolicyTest : public testing::Test {
 
   virtual void SetUp() {
     old_browser_client_ = content::GetContentClient()->browser();
-    content::GetContentClient()->set_browser(&test_browser_client_);
+    content::GetContentClient()->set_browser_for_testing(&test_browser_client_);
 
     // Claim to always handle chrome:// URLs because the CPSP's notion of
     // allowing WebUI bindings is hard-wired to this particular scheme.
@@ -59,7 +59,7 @@ class ChildProcessSecurityPolicyTest : public testing::Test {
 
   virtual void TearDown() {
     test_browser_client_.ClearSchemes();
-    content::GetContentClient()->set_browser(old_browser_client_);
+    content::GetContentClient()->set_browser_for_testing(old_browser_client_);
   }
 
  protected:
diff --git a/content/browser/debugger/devtools_manager_unittest.cc b/content/browser/debugger/devtools_manager_unittest.cc
index 51f705b..c6a1507 100644
--- a/content/browser/debugger/devtools_manager_unittest.cc
+++ b/content/browser/debugger/devtools_manager_unittest.cc
@@ -6,7 +6,6 @@
 #include "base/time.h"
 #include "content/browser/debugger/devtools_manager_impl.h"
 #include "content/browser/debugger/render_view_devtools_agent_host.h"
-#include "content/browser/mock_content_browser_client.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
 #include "content/browser/web_contents/test_web_contents.h"
 #include "content/common/view_messages.h"
@@ -14,6 +13,7 @@
 #include "content/public/browser/devtools_agent_host_registry.h"
 #include "content/public/browser/devtools_client_host.h"
 #include "content/public/browser/web_contents_delegate.h"
+#include "content/test/test_content_browser_client.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using base::TimeDelta;
@@ -92,7 +92,7 @@ class TestWebContentsDelegate : public content::WebContentsDelegate {
 };
 
 class DevToolsManagerTestBrowserClient
-    : public content::MockContentBrowserClient {
+    : public content::TestContentBrowserClient {
  public:
   DevToolsManagerTestBrowserClient() {
   }
@@ -118,7 +118,7 @@ class DevToolsManagerTest : public RenderViewHostImplTestHarness {
  protected:
   virtual void SetUp() OVERRIDE {
     original_browser_client_ = content::GetContentClient()->browser();
-    content::GetContentClient()->set_browser(&browser_client_);
+    content::GetContentClient()->set_browser_for_testing(&browser_client_);
 
     RenderViewHostImplTestHarness::SetUp();
     TestDevToolsClientHost::ResetCounters();
@@ -126,7 +126,8 @@ class DevToolsManagerTest : public RenderViewHostImplTestHarness {
 
   virtual void TearDown() OVERRIDE {
     RenderViewHostImplTestHarness::TearDown();
-    content::GetContentClient()->set_browser(original_browser_client_);
+    content::GetContentClient()->set_browser_for_testing(
+        original_browser_client_);
   }
 
  private:
diff --git a/content/browser/renderer_host/media/media_stream_dispatcher_host_unittest.cc b/content/browser/renderer_host/media/media_stream_dispatcher_host_unittest.cc
index a2c6095..0539bb8 100644
--- a/content/browser/renderer_host/media/media_stream_dispatcher_host_unittest.cc
+++ b/content/browser/renderer_host/media/media_stream_dispatcher_host_unittest.cc
@@ -7,7 +7,6 @@
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "content/browser/browser_thread_impl.h"
-#include "content/browser/mock_content_browser_client.h"
 #include "content/browser/renderer_host/media/media_stream_dispatcher_host.h"
 #include "content/browser/renderer_host/media/media_stream_manager.h"
 #include "content/browser/renderer_host/media/mock_media_observer.h"
@@ -15,6 +14,7 @@
 #include "content/common/media/media_stream_messages.h"
 #include "content/common/media/media_stream_options.h"
 #include "content/public/test/mock_resource_context.h"
+#include "content/test/test_content_browser_client.h"
 #include "content/test/test_content_client.h"
 #include "ipc/ipc_message_macros.h"
 #include "media/audio/audio_manager.h"
@@ -37,7 +37,7 @@ const int kPageRequestId = 7;
 namespace media_stream {
 
 class MockMediaStreamDispatcherHost : public MediaStreamDispatcherHost,
-                                      public content::MockContentBrowserClient {
+                                      public content::TestContentBrowserClient {
  public:
   MockMediaStreamDispatcherHost(content::ResourceContext* resource_context,
                                 MessageLoop* message_loop,
@@ -179,7 +179,7 @@ class MediaStreamDispatcherHostTest : public testing::Test {
     old_browser_client_ = content::GetContentClient()->browser();
     content_client_.reset(new TestContentClient);
     content::SetContentClient(content_client_.get());
-    content_client_->set_browser(host_);
+    content_client_->set_browser_for_testing(host_);
   }
 
   virtual void TearDown() {
@@ -187,7 +187,7 @@ class MediaStreamDispatcherHostTest : public testing::Test {
     SyncWithVideoCaptureManagerThread();
 
     // Recover the old browser client and content client.
-    content::GetContentClient()->set_browser(old_browser_client_);
+    content::GetContentClient()->set_browser_for_testing(old_browser_client_);
     content::SetContentClient(old_client_);
     content_client_.reset();
   }
diff --git a/content/browser/site_instance_impl_unittest.cc b/content/browser/site_instance_impl_unittest.cc
index b40919b..37ab73a 100644
--- a/content/browser/site_instance_impl_unittest.cc
+++ b/content/browser/site_instance_impl_unittest.cc
@@ -8,7 +8,6 @@
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/browsing_instance.h"
 #include "content/browser/child_process_security_policy_impl.h"
-#include "content/browser/mock_content_browser_client.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
@@ -22,6 +21,7 @@
 #include "content/public/test/mock_render_process_host.h"
 #include "content/public/test/test_browser_context.h"
 #include "content/public/test/test_browser_thread.h"
+#include "content/test/test_content_browser_client.h"
 #include "content/test/test_content_client.h"
 #include "googleurl/src/url_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -81,7 +81,7 @@ class SiteInstanceTestClient : public TestContentClient {
 };
 
 class SiteInstanceTestBrowserClient :
-    public content::MockContentBrowserClient {
+    public content::TestContentBrowserClient {
  public:
   SiteInstanceTestBrowserClient()
       : privileged_process_id_(-1) {
@@ -127,13 +127,13 @@ class SiteInstanceTest : public testing::Test {
     old_client_ = content::GetContentClient();
     old_browser_client_ = content::GetContentClient()->browser();
     content::SetContentClient(&client_);
-    content::GetContentClient()->set_browser(&browser_client_);
+    content::GetContentClient()->set_browser_for_testing(&browser_client_);
     url_util::AddStandardScheme(kPrivilegedScheme);
     url_util::AddStandardScheme(chrome::kChromeUIScheme);
   }
 
   virtual void TearDown() {
-    content::GetContentClient()->set_browser(old_browser_client_);
+    content::GetContentClient()->set_browser_for_testing(old_browser_client_);
     content::SetContentClient(old_client_);
     MessageLoop::current()->RunAllPending();
     message_loop_.RunAllPending();
diff --git a/content/browser/web_contents/render_view_host_manager_unittest.cc b/content/browser/web_contents/render_view_host_manager_unittest.cc
index fd94166..25705d7 100644
--- a/content/browser/web_contents/render_view_host_manager_unittest.cc
+++ b/content/browser/web_contents/render_view_host_manager_unittest.cc
@@ -4,7 +4,6 @@
 
 #include "base/utf_string_conversions.h"
 #include "content/browser/browser_thread_impl.h"
-#include "content/browser/mock_content_browser_client.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
 #include "content/browser/site_instance_impl.h"
 #include "content/browser/web_contents/navigation_controller_impl.h"
@@ -24,6 +23,7 @@
 #include "content/public/test/mock_render_process_host.h"
 #include "content/public/test/test_browser_context.h"
 #include "content/public/test/test_notification_tracker.h"
+#include "content/test/test_content_browser_client.h"
 #include "content/test/test_content_client.h"
 #include "googleurl/src/url_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -108,7 +108,7 @@ class RenderViewHostManagerTestClient : public TestContentClient {
 };
 
 class RenderViewHostManagerTestBrowserClient
-    : public content::MockContentBrowserClient {
+    : public content::TestContentBrowserClient {
  public:
   RenderViewHostManagerTestBrowserClient() {}
   virtual ~RenderViewHostManagerTestBrowserClient() {}
@@ -117,7 +117,7 @@ class RenderViewHostManagerTestBrowserClient
     factory_.set_should_create_webui(should_create_webui);
   }
 
-  // content::MockContentBrowserClient implementation.
+  // content::TestContentBrowserClient implementation.
   virtual content::WebUIControllerFactory*
       GetWebUIControllerFactory() OVERRIDE {
     return &factory_;
@@ -139,13 +139,13 @@ class RenderViewHostManagerTest
     old_client_ = content::GetContentClient();
     old_browser_client_ = content::GetContentClient()->browser();
     content::SetContentClient(&client_);
-    content::GetContentClient()->set_browser(&browser_client_);
+    content::GetContentClient()->set_browser_for_testing(&browser_client_);
     url_util::AddStandardScheme(chrome::kChromeUIScheme);
   }
 
   virtual void TearDown() OVERRIDE {
     RenderViewHostImplTestHarness::TearDown();
-    content::GetContentClient()->set_browser(old_browser_client_);
+    content::GetContentClient()->set_browser_for_testing(old_browser_client_);
     content::SetContentClient(old_client_);
   }
 
diff --git a/content/browser/web_contents/web_contents_impl_unittest.cc b/content/browser/web_contents/web_contents_impl_unittest.cc
index f40285f..77559e6 100644
--- a/content/browser/web_contents/web_contents_impl_unittest.cc
+++ b/content/browser/web_contents/web_contents_impl_unittest.cc
@@ -4,7 +4,6 @@
 
 #include "base/logging.h"
 #include "base/utf_string_conversions.h"
-#include "content/browser/mock_content_browser_client.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/renderer_host/test_render_view_host.h"
 #include "content/browser/site_instance_impl.h"
@@ -25,6 +24,7 @@
 #include "content/public/common/url_constants.h"
 #include "content/public/test/mock_render_process_host.h"
 #include "content/public/test/test_browser_thread.h"
+#include "content/test/test_content_browser_client.h"
 #include "content/test/test_content_client.h"
 #include "googleurl/src/url_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -94,7 +94,7 @@ class WebContentsImplTestContentClient : public TestContentClient {
 };
 
 class WebContentsImplTestBrowserClient
-    : public content::MockContentBrowserClient {
+    : public content::TestContentBrowserClient {
  public:
   WebContentsImplTestBrowserClient() {
   }
@@ -289,12 +289,12 @@ class WebContentsImplTest : public RenderViewHostImplTestHarness {
     old_client_ = content::GetContentClient();
     old_browser_client_ = content::GetContentClient()->browser();
     content::SetContentClient(&client_);
-    content::GetContentClient()->set_browser(&browser_client_);
+    content::GetContentClient()->set_browser_for_testing(&browser_client_);
     RenderViewHostImplTestHarness::SetUp();
   }
 
   virtual void TearDown() {
-    content::GetContentClient()->set_browser(old_browser_client_);
+    content::GetContentClient()->set_browser_for_testing(old_browser_client_);
     content::SetContentClient(old_client_);
     RenderViewHostImplTestHarness::TearDown();
   }
diff --git a/content/content_shell.gypi b/content/content_shell.gypi
index 8fc69ca..588723e 100644
--- a/content/content_shell.gypi
+++ b/content/content_shell.gypi
@@ -70,12 +70,8 @@
         'shell/shell_content_browser_client.h',
         'shell/shell_content_client.cc',
         'shell/shell_content_client.h',
-        'shell/shell_content_plugin_client.cc',
-        'shell/shell_content_plugin_client.h',
         'shell/shell_content_renderer_client.cc',
         'shell/shell_content_renderer_client.h',
-        'shell/shell_content_utility_client.cc',
-        'shell/shell_content_utility_client.h',
         'shell/shell_devtools_delegate.cc',
         'shell/shell_devtools_delegate.h',
         'shell/shell_download_manager_delegate.cc',
diff --git a/content/content_tests.gypi b/content/content_tests.gypi
index bde98e2..9784a97 100644
--- a/content/content_tests.gypi
+++ b/content/content_tests.gypi
@@ -58,8 +58,6 @@
         'browser/geolocation/fake_access_token_store.h',
         'browser/geolocation/mock_location_provider.cc',
         'browser/geolocation/mock_location_provider.h',
-        'browser/mock_content_browser_client.cc',
-        'browser/mock_content_browser_client.h',
         'browser/renderer_host/media/mock_media_observer.cc',
         'browser/renderer_host/media/mock_media_observer.h',
         'browser/renderer_host/test_backing_store.cc',
@@ -102,6 +100,8 @@
         'test/render_view_test.cc',
         'test/test_browser_context.cc',
         'test/test_browser_thread.cc',
+        'test/test_content_browser_client.cc',
+        'test/test_content_browser_client.h',
         'test/test_content_client.cc',
         'test/test_content_client.h',
         'test/test_content_client_initializer.cc',
diff --git a/content/public/DEPS b/content/public/DEPS
index b790400..7358adb 100644
--- a/content/public/DEPS
+++ b/content/public/DEPS
@@ -5,5 +5,5 @@ include_rules = [
   # included directly by embedders of content/.  It must however be
   # available to code in content/public.
   "+content/common/content_export.h",
-  "+content/public",
+  "+content/public/common",
 ]
diff --git a/content/public/app/DEPS b/content/public/app/DEPS
new file mode 100644
index 0000000..255cb72
--- /dev/null
+++ b/content/public/app/DEPS
@@ -0,0 +1,6 @@
+include_rules = [
+  "+content/public/browser/content_browser_client.h",
+  "+content/public/plugin/content_plugin_client.h",
+  "+content/public/renderer/content_renderer_client.h",
+  "+content/public/utility/content_utility_client.h",
+]
diff --git a/content/public/app/content_main_delegate.cc b/content/public/app/content_main_delegate.cc
index b8e6a6c..51a6742 100644
--- a/content/public/app/content_main_delegate.cc
+++ b/content/public/app/content_main_delegate.cc
@@ -4,6 +4,11 @@
 
 #include "content/public/app/content_main_delegate.h"
 
+#include "content/public/browser/content_browser_client.h"
+#include "content/public/plugin/content_plugin_client.h"
+#include "content/public/renderer/content_renderer_client.h"
+#include "content/public/utility/content_utility_client.h"
+
 namespace content {
 
 bool ContentMainDelegate::BasicStartupComplete(int* exit_code) {
@@ -40,4 +45,20 @@ ZygoteForkDelegate* ContentMainDelegate::ZygoteStarting() {
 
 #endif
 
+ContentBrowserClient* ContentMainDelegate::CreateContentBrowserClient() {
+  return new ContentBrowserClient();
+}
+
+ContentPluginClient* ContentMainDelegate::CreateContentPluginClient() {
+  return new ContentPluginClient();
+}
+
+ContentRendererClient* ContentMainDelegate::CreateContentRendererClient() {
+  return new ContentRendererClient();
+}
+
+ContentUtilityClient* ContentMainDelegate::CreateContentUtilityClient() {
+  return new ContentUtilityClient();
+}
+
 }  // namespace content
diff --git a/content/public/app/content_main_delegate.h b/content/public/app/content_main_delegate.h
index f98130c..e0db578 100644
--- a/content/public/app/content_main_delegate.h
+++ b/content/public/app/content_main_delegate.h
@@ -13,6 +13,10 @@
 
 namespace content {
 
+class ContentBrowserClient;
+class ContentPluginClient;
+class ContentRendererClient;
+class ContentUtilityClient;
 class ZygoteForkDelegate;
 struct MainFunctionParams;
 
@@ -68,6 +72,17 @@ class CONTENT_EXPORT ContentMainDelegate {
   // Called every time the zygote process forks.
   virtual void ZygoteForked() {}
 #endif  // OS_MACOSX
+
+ protected:
+  friend class ContentClientInitializer;
+
+  // Called once per relevant process type to allow the embedder to customize
+  // content. If an embedder wants the default (empty) implementation, don't
+  // override this.
+  virtual ContentBrowserClient* CreateContentBrowserClient();
+  virtual ContentPluginClient* CreateContentPluginClient();
+  virtual ContentRendererClient* CreateContentRendererClient();
+  virtual ContentUtilityClient* CreateContentUtilityClient();
 };
 
 }  // namespace content
diff --git a/content/public/browser/content_browser_client.h b/content/public/browser/content_browser_client.h
index d8f0e9c..3a0a825 100644
--- a/content/public/browser/content_browser_client.h
+++ b/content/public/browser/content_browser_client.h
@@ -81,6 +81,8 @@ typedef base::Callback< void(const MediaStreamDevices&) > MediaResponseCallback;
 // the observer interfaces.)
 class CONTENT_EXPORT ContentBrowserClient {
  public:
+  virtual ~ContentBrowserClient() {}
+
   // Allows the embedder to set any number of custom BrowserMainParts
   // implementations for the browser startup code. See comments in
   // browser_main_parts.h.
@@ -422,9 +424,6 @@ class CONTENT_EXPORT ContentBrowserClient {
       crypto::CryptoModuleBlockingPasswordDelegate* GetCryptoPasswordDelegate(
           const GURL& url);
 #endif
-
- protected:
-  virtual ~ContentBrowserClient() {}
 };
 
 }  // namespace content
diff --git a/content/public/common/content_client.h b/content/public/common/content_client.h
index c4cbe82..4573edf 100644
--- a/content/public/common/content_client.h
+++ b/content/public/common/content_client.h
@@ -73,13 +73,9 @@ class CONTENT_EXPORT ContentClient {
   virtual ~ContentClient();
 
   ContentBrowserClient* browser() { return browser_; }
-  void set_browser(ContentBrowserClient* c) { browser_ = c; }
   ContentPluginClient* plugin() { return plugin_; }
-  void set_plugin(ContentPluginClient* p) { plugin_ = p; }
   ContentRendererClient* renderer() { return renderer_; }
-  void set_renderer(ContentRendererClient* r) { renderer_ = r; }
   ContentUtilityClient* utility() { return utility_; }
-  void set_utility(ContentUtilityClient* u) { utility_ = u; }
 
   // Sets the currently active URL.  Use GURL() to clear the URL.
   virtual void SetActiveURL(const GURL& url) {}
@@ -139,7 +135,12 @@ class CONTENT_EXPORT ContentClient {
       int* sandbox_profile_resource_id) const;
 #endif
 
+  void set_browser_for_testing(ContentBrowserClient* c) { browser_ = c; }
+  void set_renderer_for_testing(ContentRendererClient* r) { renderer_ = r; }
+
  private:
+  friend class ContentClientInitializer;  // To set these pointers.
+
   // The embedder API for participating in browser logic.
   ContentBrowserClient* browser_;
   // The embedder API for participating in plugin logic.
diff --git a/content/public/plugin/content_plugin_client.h b/content/public/plugin/content_plugin_client.h
index 499579a..96cb641 100644
--- a/content/public/plugin/content_plugin_client.h
+++ b/content/public/plugin/content_plugin_client.h
@@ -14,11 +14,10 @@ namespace content {
 // Embedder API for participating in plugin logic.
 class CONTENT_EXPORT ContentPluginClient {
  public:
+  virtual ~ContentPluginClient() {}
+
   // Notifies that a plugin process has started.
   virtual void PluginProcessStarted(const string16& plugin_name) {}
-
- protected:
-  virtual ~ContentPluginClient() {}
 };
 
 }  // namespace content
diff --git a/content/public/test/test_content_client_initializer.h b/content/public/test/test_content_client_initializer.h
index 40ccd54..2e2af48 100644
--- a/content/public/test/test_content_client_initializer.h
+++ b/content/public/test/test_content_client_initializer.h
@@ -14,8 +14,8 @@ class NotificationServiceImpl;
 namespace content {
 
 class ContentClient;
-class MockContentBrowserClient;
 class MockRenderProcessHostFactory;
+class TestContentBrowserClient;
 class TestRenderViewHostFactory;
 
 // Initializes various objects needed to run unit tests that use content::
@@ -34,7 +34,7 @@ class TestContentClientInitializer {
  private:
   scoped_ptr<NotificationServiceImpl> notification_service_;
   scoped_ptr<ContentClient> content_client_;
-  scoped_ptr<MockContentBrowserClient> content_browser_client_;
+  scoped_ptr<TestContentBrowserClient> content_browser_client_;
   scoped_ptr<content::MockRenderProcessHostFactory> rph_factory_;
   scoped_ptr<TestRenderViewHostFactory> test_render_view_host_factory_;
 
diff --git a/content/renderer/mock_content_renderer_client.cc b/content/renderer/mock_content_renderer_client.cc
deleted file mode 100644
index 664aff1..0000000
--- a/content/renderer/mock_content_renderer_client.cc
+++ /dev/null
@@ -1,145 +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/renderer/mock_content_renderer_client.h"
-
-#include <string>
-#include "v8/include/v8.h"
-
-namespace content {
-
-MockContentRendererClient::~MockContentRendererClient() {
-}
-
-void MockContentRendererClient::RenderThreadStarted() {
-}
-
-void MockContentRendererClient::RenderViewCreated(RenderView* render_view) {
-}
-
-void MockContentRendererClient::SetNumberOfViews(int number_of_views) {
-}
-
-SkBitmap* MockContentRendererClient::GetSadPluginBitmap() {
-  return NULL;
-}
-
-std::string MockContentRendererClient::GetDefaultEncoding() {
-  return std::string();
-}
-
-bool MockContentRendererClient::OverrideCreatePlugin(
-    RenderView* render_view,
-    WebKit::WebFrame* frame,
-    const WebKit::WebPluginParams& params,
-    WebKit::WebPlugin** plugin) {
-  return false;
-}
-
-WebKit::WebPlugin* MockContentRendererClient::CreatePluginReplacement(
-    RenderView* render_view,
-    const FilePath& plugin_path) {
-  return NULL;
-}
-
-bool MockContentRendererClient::HasErrorPage(int http_status_code,
-                                             std::string* error_domain) {
-  return false;
-}
-
-webkit_media::WebMediaPlayerImpl*
-MockContentRendererClient::OverrideCreateWebMediaPlayer(
-    RenderView* render_view,
-    WebKit::WebFrame* frame,
-    WebKit::WebMediaPlayerClient* client,
-    base::WeakPtr<webkit_media::WebMediaPlayerDelegate> delegate,
-    media::FilterCollection* collection,
-    WebKit::WebAudioSourceProvider* audio_source_provider,
-    media::MessageLoopFactory* message_loop_factory,
-    webkit_media::MediaStreamClient* media_stream_client,
-    media::MediaLog* media_log) {
-  return NULL;
-}
-
-void MockContentRendererClient::GetNavigationErrorStrings(
-    const WebKit::WebURLRequest& failed_request,
-    const WebKit::WebURLError& error,
-    std::string* error_html,
-    string16* error_description) {
-}
-
-bool MockContentRendererClient::RunIdleHandlerWhenWidgetsHidden() {
-  return true;
-}
-
-bool MockContentRendererClient::AllowPopup(const GURL& creator) {
-  return false;
-}
-
-bool MockContentRendererClient::ShouldFork(WebKit::WebFrame* frame,
-                                           const GURL& url,
-                                           bool is_initial_navigation,
-                                           bool* send_referrer) {
-  return false;
-}
-
-bool MockContentRendererClient::WillSendRequest(WebKit::WebFrame* frame,
-                                                const GURL& url,
-                                                GURL* new_url) {
-  return false;
-}
-
-bool MockContentRendererClient::ShouldPumpEventsDuringCookieMessage() {
-  return false;
-}
-
-void MockContentRendererClient::DidCreateScriptContext(
-    WebKit::WebFrame* frame, v8::Handle<v8::Context> context,
-    int extension_group, int world_id) {
-}
-
-void MockContentRendererClient::WillReleaseScriptContext(
-    WebKit::WebFrame* frame, v8::Handle<v8::Context> context, int world_id) {
-}
-
-unsigned long long MockContentRendererClient::VisitedLinkHash(
-    const char* canonical_url, size_t length) {
-  return 0LL;
-}
-
-bool MockContentRendererClient::IsLinkVisited(unsigned long long link_hash) {
-  return false;
-}
-
-void MockContentRendererClient::PrefetchHostName(
-    const char* hostname, size_t length) {
-}
-
-bool MockContentRendererClient::ShouldOverridePageVisibilityState(
-    const RenderView* render_view,
-    WebKit::WebPageVisibilityState* override_state) const {
-  return false;
-}
-
-bool MockContentRendererClient::HandleGetCookieRequest(
-    RenderView* sender,
-    const GURL& url,
-    const GURL& first_party_for_cookies,
-    std::string* cookies) {
-  return false;
-}
-
-bool MockContentRendererClient::HandleSetCookieRequest(
-    RenderView* sender,
-    const GURL& url,
-    const GURL& first_party_for_cookies,
-    const std::string& value) {
-  return false;
-}
-
-void MockContentRendererClient::RegisterPPAPIInterfaceFactories(
-    webkit::ppapi::PpapiInterfaceFactoryManager* factory_manager) {
-}
-
-}  // namespace content
diff --git a/content/renderer/mock_content_renderer_client.h b/content/renderer/mock_content_renderer_client.h
deleted file mode 100644
index 82fae79..0000000
--- a/content/renderer/mock_content_renderer_client.h
+++ /dev/null
@@ -1,88 +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.
-
-#ifndef CONTENT_RENDERER_MOCK_CONTENT_RENDERER_CLIENT_H_
-#define CONTENT_RENDERER_MOCK_CONTENT_RENDERER_CLIENT_H_
-#pragma once
-
-#include <string>
-
-#include "base/compiler_specific.h"
-#include "content/public/renderer/content_renderer_client.h"
-
-namespace content {
-
-// Base class for unit tests that need to mock the ContentRendererClient.
-class MockContentRendererClient : public ContentRendererClient {
- public:
-  virtual ~MockContentRendererClient();
-  virtual void RenderThreadStarted() OVERRIDE;
-  virtual void RenderViewCreated(RenderView* render_view) OVERRIDE;
-  virtual void SetNumberOfViews(int number_of_views) OVERRIDE;
-  virtual SkBitmap* GetSadPluginBitmap() OVERRIDE;
-  virtual std::string GetDefaultEncoding() OVERRIDE;
-  virtual bool OverrideCreatePlugin(
-      RenderView* render_view,
-      WebKit::WebFrame* frame,
-      const WebKit::WebPluginParams& params,
-      WebKit::WebPlugin** plugin) OVERRIDE;
-  virtual WebKit::WebPlugin* CreatePluginReplacement(
-      RenderView* render_view,
-      const FilePath& plugin_path) OVERRIDE;
-  virtual bool HasErrorPage(int http_status_code,
-                            std::string* error_domain) OVERRIDE;
-  virtual void GetNavigationErrorStrings(
-      const WebKit::WebURLRequest& failed_request,
-      const WebKit::WebURLError& error,
-      std::string* error_html,
-      string16* error_description) OVERRIDE;
-  virtual webkit_media::WebMediaPlayerImpl* OverrideCreateWebMediaPlayer(
-      RenderView* render_view,
-      WebKit::WebFrame* frame,
-      WebKit::WebMediaPlayerClient* client,
-      base::WeakPtr<webkit_media::WebMediaPlayerDelegate> delegate,
-      media::FilterCollection* collection,
-      WebKit::WebAudioSourceProvider* audio_source_provider,
-      media::MessageLoopFactory* message_loop_factory,
-      webkit_media::MediaStreamClient* media_stream_client,
-      media::MediaLog* media_log) OVERRIDE;
-  virtual bool RunIdleHandlerWhenWidgetsHidden() OVERRIDE;
-  virtual bool AllowPopup(const GURL& creator) OVERRIDE;
-  virtual bool ShouldFork(WebKit::WebFrame* frame,
-                          const GURL& url,
-                          bool is_initial_navigation,
-                          bool* send_referrer) OVERRIDE;
-  virtual bool WillSendRequest(WebKit::WebFrame* frame,
-                               const GURL& url,
-                               GURL* new_url) OVERRIDE;
-  virtual bool ShouldPumpEventsDuringCookieMessage() OVERRIDE;
-  virtual void DidCreateScriptContext(WebKit::WebFrame* frame,
-                                      v8::Handle<v8::Context> context,
-                                      int extension_group,
-                                      int world_id) OVERRIDE;
-  virtual void WillReleaseScriptContext(WebKit::WebFrame* frame,
-                                        v8::Handle<v8::Context> context,
-                                        int world_id) OVERRIDE;
-  virtual unsigned long long VisitedLinkHash(const char* canonical_url,
-                                             size_t length) OVERRIDE;
-  virtual bool IsLinkVisited(unsigned long long link_hash) OVERRIDE;
-  virtual void PrefetchHostName(const char* hostname, size_t length) OVERRIDE;
-  virtual bool ShouldOverridePageVisibilityState(
-      const RenderView* render_view,
-      WebKit::WebPageVisibilityState* override_state) const OVERRIDE;
-  virtual bool HandleGetCookieRequest(RenderView* sender,
-                                      const GURL& url,
-                                      const GURL& first_party_for_cookies,
-                                      std::string* cookies) OVERRIDE;
-  virtual bool HandleSetCookieRequest(RenderView* sender,
-                                      const GURL& url,
-                                      const GURL& first_party_for_cookies,
-                                      const std::string& value) OVERRIDE;
-  virtual void RegisterPPAPIInterfaceFactories(
-      webkit::ppapi::PpapiInterfaceFactoryManager* factory_manager) OVERRIDE;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_RENDERER_MOCK_CONTENT_RENDERER_CLIENT_H_
diff --git a/content/shell/shell_content_plugin_client.cc b/content/shell/shell_content_plugin_client.cc
deleted file mode 100644
index b2b6c7d..0000000
--- a/content/shell/shell_content_plugin_client.cc
+++ /dev/null
@@ -1,12 +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.
-
-#include "content/shell/shell_content_plugin_client.h"
-
-namespace content {
-
-ShellContentPluginClient::~ShellContentPluginClient() {
-}
-
-}  // namespace content
diff --git a/content/shell/shell_content_plugin_client.h b/content/shell/shell_content_plugin_client.h
deleted file mode 100644
index f35937a..0000000
--- a/content/shell/shell_content_plugin_client.h
+++ /dev/null
@@ -1,21 +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_SHELL_SHELL_CONTENT_PLUGIN_CLIENT_H_
-#define CONTENT_SHELL_SHELL_CONTENT_PLUGIN_CLIENT_H_
-#pragma once
-
-#include "base/compiler_specific.h"
-#include "content/public/plugin/content_plugin_client.h"
-
-namespace content {
-
-class ShellContentPluginClient : public ContentPluginClient {
- public:
-  virtual ~ShellContentPluginClient();
-};
-
-}  // namespace content
-
-#endif  // CONTENT_SHELL_SHELL_CONTENT_PLUGIN_CLIENT_H_
diff --git a/content/shell/shell_content_utility_client.cc b/content/shell/shell_content_utility_client.cc
deleted file mode 100644
index fb2a285..0000000
--- a/content/shell/shell_content_utility_client.cc
+++ /dev/null
@@ -1,19 +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.
-
-#include "content/shell/shell_content_utility_client.h"
-
-namespace content {
-
-ShellContentUtilityClient::~ShellContentUtilityClient() {
-}
-
-void ShellContentUtilityClient::UtilityThreadStarted() {
-}
-
-bool ShellContentUtilityClient::OnMessageReceived(const IPC::Message& message) {
-  return false;
-}
-
-}  // namespace content
diff --git a/content/shell/shell_content_utility_client.h b/content/shell/shell_content_utility_client.h
deleted file mode 100644
index 051298a..0000000
--- a/content/shell/shell_content_utility_client.h
+++ /dev/null
@@ -1,23 +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_SHELL_SHELL_CONTENT_UTILITY_CLIENT_H_
-#define CONTENT_SHELL_SHELL_CONTENT_UTILITY_CLIENT_H_
-#pragma once
-
-#include "base/compiler_specific.h"
-#include "content/public/utility/content_utility_client.h"
-
-namespace content {
-
-  class ShellContentUtilityClient : public ContentUtilityClient {
- public:
-  virtual ~ShellContentUtilityClient();
-  virtual void UtilityThreadStarted() OVERRIDE;
-  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_SHELL_SHELL_CONTENT_UTILITY_CLIENT_H_
diff --git a/content/shell/shell_main_delegate.cc b/content/shell/shell_main_delegate.cc
index 469e779..f2ae251 100644
--- a/content/shell/shell_main_delegate.cc
+++ b/content/shell/shell_main_delegate.cc
@@ -11,9 +11,7 @@
 #include "content/public/common/url_constants.h"
 #include "content/shell/shell_browser_main.h"
 #include "content/shell/shell_content_browser_client.h"
-#include "content/shell/shell_content_plugin_client.h"
 #include "content/shell/shell_content_renderer_client.h"
-#include "content/shell/shell_content_utility_client.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
 
@@ -34,12 +32,7 @@ bool ShellMainDelegate::BasicStartupComplete(int* exit_code) {
 #if defined(OS_MACOSX)
   OverrideFrameworkBundlePath();
 #endif
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  std::string process_type =
-      command_line.GetSwitchValueASCII(switches::kProcessType);
   content::SetContentClient(&content_client_);
-  InitializeShellContentClient(process_type);
-
   return false;
 }
 
@@ -59,35 +52,6 @@ int ShellMainDelegate::RunProcess(
   return ShellBrowserMain(main_function_params);
 }
 
-#if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
-void ShellMainDelegate::ZygoteForked() {
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  std::string process_type =
-      command_line.GetSwitchValueASCII(switches::kProcessType);
-  InitializeShellContentClient(process_type);
-}
-#endif
-
-void ShellMainDelegate::InitializeShellContentClient(
-    const std::string& process_type) {
-  if (process_type.empty()) {
-    browser_client_.reset(new content::ShellContentBrowserClient);
-    content::GetContentClient()->set_browser(browser_client_.get());
-  }
-
-  if (process_type == switches::kRendererProcess ||
-      CommandLine::ForCurrentProcess()->HasSwitch(switches::kSingleProcess)) {
-    renderer_client_.reset(new content::ShellContentRendererClient);
-    content::GetContentClient()->set_renderer(renderer_client_.get());
-  } else if (process_type == switches::kPluginProcess) {
-    plugin_client_.reset(new content::ShellContentPluginClient);
-    content::GetContentClient()->set_plugin(plugin_client_.get());
-  } else if (process_type == switches::kUtilityProcess) {
-    utility_client_.reset(new content::ShellContentUtilityClient);
-    content::GetContentClient()->set_utility(utility_client_.get());
-  }
-}
-
 void ShellMainDelegate::InitializeResourceBundle() {
   FilePath pak_file;
 #if defined(OS_MACOSX)
@@ -106,3 +70,14 @@ void ShellMainDelegate::InitializeResourceBundle() {
 #endif
   ui::ResourceBundle::InitSharedInstanceWithPakFile(pak_file);
 }
+
+content::ContentBrowserClient* ShellMainDelegate::CreateContentBrowserClient() {
+  browser_client_.reset(new content::ShellContentBrowserClient);
+  return browser_client_.get();
+}
+
+content::ContentRendererClient*
+    ShellMainDelegate::CreateContentRendererClient() {
+  renderer_client_.reset(new content::ShellContentRendererClient);
+  return renderer_client_.get();
+}
diff --git a/content/shell/shell_main_delegate.h b/content/shell/shell_main_delegate.h
index d3b07d4..a36dbcc 100644
--- a/content/shell/shell_main_delegate.h
+++ b/content/shell/shell_main_delegate.h
@@ -14,8 +14,6 @@
 namespace content {
 class ShellContentBrowserClient;
 class ShellContentRendererClient;
-class ShellContentPluginClient;
-class ShellContentUtilityClient;
 }  // namespace content
 
 class ShellMainDelegate : public content::ContentMainDelegate {
@@ -23,23 +21,21 @@ class ShellMainDelegate : public content::ContentMainDelegate {
   ShellMainDelegate();
   virtual ~ShellMainDelegate();
 
+  // content::ContentMainDelegate implementation:
   virtual bool BasicStartupComplete(int* exit_code) OVERRIDE;
   virtual void PreSandboxStartup() OVERRIDE;
   virtual int RunProcess(
       const std::string& process_type,
       const content::MainFunctionParams& main_function_params) OVERRIDE;
-#if defined(OS_POSIX) && !defined(OS_MACOSX) && !defined(OS_ANDROID)
-  virtual void ZygoteForked() OVERRIDE;
-#endif
+  virtual content::ContentBrowserClient* CreateContentBrowserClient() OVERRIDE;
+  virtual content::ContentRendererClient*
+      CreateContentRendererClient() OVERRIDE;
 
  private:
-  void InitializeShellContentClient(const std::string& process_type);
   void InitializeResourceBundle();
 
   scoped_ptr<content::ShellContentBrowserClient> browser_client_;
   scoped_ptr<content::ShellContentRendererClient> renderer_client_;
-  scoped_ptr<content::ShellContentPluginClient> plugin_client_;
-  scoped_ptr<content::ShellContentUtilityClient> utility_client_;
   content::ShellContentClient content_client_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellMainDelegate);
diff --git a/content/test/content_test_suite.cc b/content/test/content_test_suite.cc
index 6b785aa..1fc9d35 100644
--- a/content/test/content_test_suite.cc
+++ b/content/test/content_test_suite.cc
@@ -5,7 +5,6 @@
 #include "content/test/content_test_suite.h"
 
 #include "base/logging.h"
-#include "content/browser/mock_content_browser_client.h"
 #include "content/public/test/test_content_client_initializer.h"
 #include "content/test/test_content_client.h"
 #include "testing/gtest/include/gtest/gtest.h"
diff --git a/content/test/render_view_fake_resources_test.cc b/content/test/render_view_fake_resources_test.cc
index 4ba5108..53c431a 100644
--- a/content/test/render_view_fake_resources_test.cc
+++ b/content/test/render_view_fake_resources_test.cc
@@ -57,7 +57,7 @@ void RenderViewFakeResourcesTest::SetUp() {
   // but we use a real RenderThread so that we can use the ResourceDispatcher
   // to fetch network resources.  These are then served canned content
   // in OnRequestResource().
-  GetContentClient()->set_renderer(&content_renderer_client_);
+  GetContentClient()->set_renderer_for_testing(&content_renderer_client_);
   // Generate a unique channel id so that multiple instances of the test can
   // run in parallel.
   std::string channel_id = IPC::Channel::GenerateVerifiedChannelID(
diff --git a/content/test/render_view_test.cc b/content/test/render_view_test.cc
index bc216acd..c8e8425 100644
--- a/content/test/render_view_test.cc
+++ b/content/test/render_view_test.cc
@@ -124,7 +124,7 @@ void RenderViewTest::SetUp() {
   // Subclasses can set the ContentClient's renderer before calling
   // RenderViewTest::SetUp().
   if (!GetContentClient()->renderer())
-    GetContentClient()->set_renderer(&content_renderer_client_);
+    GetContentClient()->set_renderer_for_testing(&content_renderer_client_);
 
   // Subclasses can set render_thread_ with their own implementation before
   // calling RenderViewTest::SetUp().
diff --git a/content/browser/mock_content_browser_client.cc b/content/test/test_content_browser_client.cc
index e0230ba..e06bff3 100644
--- a/content/browser/mock_content_browser_client.cc
+++ b/content/test/test_content_browser_client.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/browser/mock_content_browser_client.h"
+#include "content/test/test_content_browser_client.h"
 
 #include <string>
 
@@ -15,13 +15,13 @@
 
 namespace content {
 
-MockContentBrowserClient::MockContentBrowserClient() {
+TestContentBrowserClient::TestContentBrowserClient() {
 }
 
-MockContentBrowserClient::~MockContentBrowserClient() {
+TestContentBrowserClient::~TestContentBrowserClient() {
 }
 
-WebContentsView* MockContentBrowserClient::OverrideCreateWebContentsView(
+WebContentsView* TestContentBrowserClient::OverrideCreateWebContentsView(
     WebContents* web_contents,
     RenderViewHostDelegateView** render_view_host_delegate_view) {
   TestWebContentsView* rv = new TestWebContentsView;
@@ -29,7 +29,7 @@ WebContentsView* MockContentBrowserClient::OverrideCreateWebContentsView(
   return rv;
 }
 
-FilePath MockContentBrowserClient::GetDefaultDownloadDirectory() {
+FilePath TestContentBrowserClient::GetDefaultDownloadDirectory() {
   if (!download_dir_.IsValid()) {
     bool result = download_dir_.CreateUniqueTempDir();
     CHECK(result);
diff --git a/content/browser/mock_content_browser_client.h b/content/test/test_content_browser_client.h
index b497a87..b376c57 100644
--- a/content/browser/mock_content_browser_client.h
+++ b/content/test/test_content_browser_client.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CONTENT_BROWSER_MOCK_CONTENT_BROWSER_CLIENT_H_
-#define CONTENT_BROWSER_MOCK_CONTENT_BROWSER_CLIENT_H_
+#ifndef CONTENT_TEST_TEST_CONTENT_BROWSER_CLIENT_H_
+#define CONTENT_TEST_TEST_CONTENT_BROWSER_CLIENT_H_
 #pragma once
 
 #include <string>
@@ -15,11 +15,11 @@
 
 namespace content {
 
-// Base for unit tests that need to mock the ContentBrowserClient.
-class MockContentBrowserClient : public ContentBrowserClient {
+// Base for unit tests that need a ContentBrowserClient.
+class TestContentBrowserClient : public ContentBrowserClient {
  public:
-  MockContentBrowserClient();
-  virtual ~MockContentBrowserClient();
+  TestContentBrowserClient();
+  virtual ~TestContentBrowserClient();
 
   virtual WebContentsView* OverrideCreateWebContentsView(
       WebContents* web_contents,
@@ -30,9 +30,9 @@ class MockContentBrowserClient : public ContentBrowserClient {
   // Temporary directory for GetDefaultDownloadDirectory.
   ScopedTempDir download_dir_;
 
-  DISALLOW_COPY_AND_ASSIGN(MockContentBrowserClient);
+  DISALLOW_COPY_AND_ASSIGN(TestContentBrowserClient);
 };
 
 }  // namespace content
 
-#endif  // CONTENT_BROWSER_MOCK_CONTENT_BROWSER_CLIENT_H_
+#endif  // CONTENT_TEST_TEST_CONTENT_BROWSER_CLIENT_H_
diff --git a/content/test/test_content_client_initializer.cc b/content/test/test_content_client_initializer.cc
index 8783272..59a54fe 100644
--- a/content/test/test_content_client_initializer.cc
+++ b/content/test/test_content_client_initializer.cc
@@ -4,10 +4,10 @@
 
 #include "content/public/test/test_content_client_initializer.h"
 
-#include "content/browser/mock_content_browser_client.h"
 #include "content/browser/notification_service_impl.h"
 #include "content/public/common/content_client.h"
 #include "content/public/test/mock_render_process_host.h"
+#include "content/test/test_content_browser_client.h"
 #include "content/test/test_content_client.h"
 #include "content/test/test_render_view_host_factory.h"
 
@@ -20,8 +20,8 @@ TestContentClientInitializer::TestContentClientInitializer() {
   content_client_.reset(new TestContentClient);
   SetContentClient(content_client_.get());
 
-  content_browser_client_.reset(new MockContentBrowserClient());
-  content_client_->set_browser(content_browser_client_.get());
+  content_browser_client_.reset(new TestContentBrowserClient());
+  content_client_->set_browser_for_testing(content_browser_client_.get());
 }
 
 TestContentClientInitializer::~TestContentClientInitializer() {
diff --git a/content/test/webrtc_audio_device_test.cc b/content/test/webrtc_audio_device_test.cc
index 6826daa..70d829c 100644
--- a/content/test/webrtc_audio_device_test.cc
+++ b/content/test/webrtc_audio_device_test.cc
@@ -68,11 +68,11 @@ class ReplaceContentClientRenderer {
   explicit ReplaceContentClientRenderer(
       content::ContentRendererClient* new_renderer) {
     saved_renderer_ = content::GetContentClient()->renderer();
-    content::GetContentClient()->set_renderer(new_renderer);
+    content::GetContentClient()->set_renderer_for_testing(new_renderer);
   }
   ~ReplaceContentClientRenderer() {
     // Restore the original renderer.
-    content::GetContentClient()->set_renderer(saved_renderer_);
+    content::GetContentClient()->set_renderer_for_testing(saved_renderer_);
   }
  private:
   content::ContentRendererClient* saved_renderer_;
@@ -123,7 +123,7 @@ void WebRTCAudioDeviceTest::SetUp() {
   // Main parts are inspired by the RenderViewFakeResourcesTest.
   // Note that, the IPC part is not utilized in this test.
   saved_content_renderer_.reset(
-      new ReplaceContentClientRenderer(&mock_content_renderer_client_));
+      new ReplaceContentClientRenderer(&content_renderer_client_));
   mock_process_.reset(new WebRTCMockRenderProcess());
   ui_thread_.reset(new content::TestBrowserThread(content::BrowserThread::UI,
                                                   MessageLoop::current()));
diff --git a/content/test/webrtc_audio_device_test.h b/content/test/webrtc_audio_device_test.h
index 1e136f2..c0f9954 100644
--- a/content/test/webrtc_audio_device_test.h
+++ b/content/test/webrtc_audio_device_test.h
@@ -13,7 +13,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "content/browser/renderer_host/media/mock_media_observer.h"
-#include "content/renderer/mock_content_renderer_client.h"
+#include "content/public/renderer/content_renderer_client.h"
 #include "media/base/channel_layout.h"
 #include "ipc/ipc_channel.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -164,7 +164,7 @@ class WebRTCAudioDeviceTest
 
   scoped_ptr<ReplaceContentClientRenderer> saved_content_renderer_;
   MessageLoopForUI message_loop_;
-  content::MockContentRendererClient mock_content_renderer_client_;
+  content::ContentRendererClient content_renderer_client_;
   RenderThreadImpl* render_thread_;  // Owned by mock_process_.
   scoped_ptr<WebRTCMockRenderProcess> mock_process_;
   scoped_ptr<MockMediaObserver> media_observer_;
diff --git a/ui/views/examples/content_client/examples_main_delegate.cc b/ui/views/examples/content_client/examples_main_delegate.cc
index 3a2a458..1883ed0 100644
--- a/ui/views/examples/content_client/examples_main_delegate.cc
+++ b/ui/views/examples/content_client/examples_main_delegate.cc
@@ -11,9 +11,6 @@
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "content/public/common/content_switches.h"
-#include "content/shell/shell_content_plugin_client.h"
-#include "content/shell/shell_content_renderer_client.h"
-#include "content/shell/shell_content_utility_client.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
 #include "ui/views/examples/content_client/examples_content_browser_client.h"
@@ -47,7 +44,6 @@ bool ExamplesMainDelegate::BasicStartupComplete(int* exit_code) {
       command_line.GetSwitchValueASCII(switches::kProcessType);
 
   content::SetContentClient(&content_client_);
-  InitializeShellContentClient(process_type);
 
   bool success = logging::InitLogging(NULL,
       logging::LOG_ONLY_TO_SYSTEM_DEBUG_LOG,
@@ -66,30 +62,10 @@ void ExamplesMainDelegate::PreSandboxStartup() {
   InitializeResourceBundle();
 }
 
-#if defined(OS_POSIX)
-void ExamplesMainDelegate::ZygoteForked() {
-  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
-  std::string process_type =
-      command_line.GetSwitchValueASCII(switches::kProcessType);
-  InitializeShellContentClient(process_type);
-}
-#endif
-
-void ExamplesMainDelegate::InitializeShellContentClient(
-    const std::string& process_type) {
-  if (process_type.empty()) {
-    browser_client_.reset(new ExamplesContentBrowserClient);
-    content::GetContentClient()->set_browser(browser_client_.get());
-  } else if (process_type == switches::kRendererProcess) {
-    renderer_client_.reset(new content::ShellContentRendererClient);
-    content::GetContentClient()->set_renderer(renderer_client_.get());
-  } else if (process_type == switches::kPluginProcess) {
-    plugin_client_.reset(new content::ShellContentPluginClient);
-    content::GetContentClient()->set_plugin(plugin_client_.get());
-  } else if (process_type == switches::kUtilityProcess) {
-    utility_client_.reset(new content::ShellContentUtilityClient);
-    content::GetContentClient()->set_utility(utility_client_.get());
-  }
+content::ContentBrowserClient*
+    ExamplesMainDelegate::CreateContentBrowserClient() {
+  browser_client_.reset(new ExamplesContentBrowserClient);
+  return browser_client_.get();
 }
 
 void ExamplesMainDelegate::InitializeResourceBundle() {
diff --git a/ui/views/examples/content_client/examples_main_delegate.h b/ui/views/examples/content_client/examples_main_delegate.h
index cecb673..750a3ff 100644
--- a/ui/views/examples/content_client/examples_main_delegate.h
+++ b/ui/views/examples/content_client/examples_main_delegate.h
@@ -14,12 +14,6 @@
 #include "content/public/app/content_main_delegate.h"
 #include "content/shell/shell_content_client.h"
 
-namespace content {
-class ShellContentRendererClient;
-class ShellContentPluginClient;
-class ShellContentUtilityClient;
-}
-
 namespace views {
 namespace examples {
 
@@ -30,20 +24,15 @@ class ExamplesMainDelegate : public content::ContentMainDelegate {
   ExamplesMainDelegate();
   virtual ~ExamplesMainDelegate();
 
+  // content::ContentMainDelegate implementation
   virtual bool BasicStartupComplete(int* exit_code) OVERRIDE;
   virtual void PreSandboxStartup() OVERRIDE;
-#if defined(OS_POSIX)
-  virtual void ZygoteForked() OVERRIDE;
-#endif  // OS_MACOSX
+  virtual content::ContentBrowserClient* CreateContentBrowserClient() OVERRIDE;
 
  private:
-  void InitializeShellContentClient(const std::string& process_type);
   void InitializeResourceBundle();
 
   scoped_ptr<ExamplesContentBrowserClient> browser_client_;
-  scoped_ptr<content::ShellContentRendererClient> renderer_client_;
-  scoped_ptr<content::ShellContentPluginClient> plugin_client_;
-  scoped_ptr<content::ShellContentUtilityClient> utility_client_;
   content::ShellContentClient content_client_;
 
   DISALLOW_COPY_AND_ASSIGN(ExamplesMainDelegate);