Add shell::Tracer object and wire up to --trace-startup on Android

shell/android/main.cc

 // Copyright 2013 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 "shell/android/main.h"
 
 #include "base/android/fifo_utils.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/threading/simple_thread.h"
+#include "base/trace_event/trace_event.h"
 #include "jni/ShellMain_jni.h"
 #include "mojo/common/message_pump_mojo.h"
 #include "shell/android/android_handler_loader.h"
 #include "shell/android/background_application_loader.h"
 #include "shell/android/native_viewport_application_loader.h"
 #include "shell/android/ui_application_loader_android.h"
 #include "shell/application_manager/application_loader.h"
 #include "shell/command_line_util.h"
 #include "shell/context.h"
 #include "shell/init.h"
+#include "shell/switches.h"
+#include "shell/tracer.h"
 #include "ui/gl/gl_surface_egl.h"
 
 using base::LazyInstance;
 
 namespace mojo {
 namespace shell {
 
 namespace {
 
 // Tag for logging.
@@ skipping 20 matching lines @@
     LAZY_INSTANCE_INITIALIZER;
 
 LazyInstance<scoped_ptr<Context>> g_context = LAZY_INSTANCE_INITIALIZER;
 
 LazyInstance<scoped_ptr<MojoShellRunner>> g_shell_runner =
     LAZY_INSTANCE_INITIALIZER;
 
 LazyInstance<scoped_ptr<base::DelegateSimpleThread>> g_shell_thread =
     LAZY_INSTANCE_INITIALIZER;
 
-LazyInstance<base::android::ScopedJavaGlobalRef<jobject>> g_main_activiy =
+LazyInstance<base::android::ScopedJavaGlobalRef<jobject>> g_main_activity =
     LAZY_INSTANCE_INITIALIZER;
 
 void ConfigureAndroidServices(Context* context) {
   context->application_manager()->SetLoaderForURL(
       make_scoped_ptr(new UIApplicationLoader(
           make_scoped_ptr(new NativeViewportApplicationLoader()),
           g_java_message_loop.Get().get())),
       GURL("mojo:native_viewport_service"));
 
   // Android handler is bundled with the Mojo shell, because it uses the
   // MojoShell application as the JNI bridge to bootstrap execution of other
   // Android Mojo apps that need JNI.
   context->application_manager()->SetLoaderForURL(
       make_scoped_ptr(new BackgroundApplicationLoader(
           make_scoped_ptr(new AndroidHandlerLoader()), "android_handler",
           base::MessageLoop::TYPE_DEFAULT)),
       GURL("mojo:android_handler"));
 
   // By default, the keyboard is handled by the native_viewport_service.
   context->url_resolver()->AddURLMapping(GURL("mojo:keyboard"),
                                          GURL("mojo:native_viewport_service"));
 }
 
 void QuitShellThread() {
   g_shell_thread.Get()->Join();
   g_shell_thread.Pointer()->reset();
   Java_ShellMain_finishActivity(base::android::AttachCurrentThread(),
-                                g_main_activiy.Get().obj());
+                                g_main_activity.Get().obj());
   exit(0);
 }
 
 void MojoShellRunner::Run() {
   base::MessageLoop loop(common::MessagePumpMojo::Create());
   Context* context = g_context.Pointer()->get();
   ConfigureAndroidServices(context);
   context->Init();
 
   for (auto& args : parameters_)
@@ skipping 27 matching lines @@
 
 }  // namespace
 
 static void Init(JNIEnv* env,
                  jclass clazz,
                  jobject activity,
                  jstring mojo_shell_path,
                  jobjectArray jparameters,
                  jstring j_local_apps_directory,
                  jstring j_tmp_dir) {
-  g_main_activiy.Get().Reset(env, activity);
+  g_main_activity.Get().Reset(env, activity);
 
+  std::string tmp_dir = base::android::ConvertJavaStringToUTF8(env, j_tmp_dir);
   // Setting the TMPDIR environment variable so that applications can use it.
   // TODO(qsr) We will need our subprocesses to inherit this.
-  int return_value =
-      setenv("TMPDIR",
-             base::android::ConvertJavaStringToUTF8(env, j_tmp_dir).c_str(), 1);
+  int return_value = setenv("TMPDIR", tmp_dir.c_str(), 1);
   DCHECK_EQ(return_value, 0);
 
   base::android::ScopedJavaLocalRef<jobject> scoped_activity(env, activity);
   base::android::InitApplicationContext(env, scoped_activity);
 
   std::vector<std::string> parameters;
   parameters.push_back(
       base::android::ConvertJavaStringToUTF8(env, mojo_shell_path));
   base::android::AppendJavaStringArrayToStringVector(env, jparameters,
                                                      &parameters);
   base::CommandLine::Init(0, nullptr);
-  base::CommandLine::ForCurrentProcess()->InitFromArgv(parameters);
+  base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+  command_line->InitFromArgv(parameters);
+  Tracer tracer;
+  bool trace_startup = command_line->HasSwitch(switches::kTraceStartup);
+  if (trace_startup)
+    tracer.Start(command_line->GetSwitchValueASCII(switches::kTraceStartup));
+
   g_shell_runner.Get().reset(new MojoShellRunner(parameters));
 
   InitializeLogging();
 
   InitializeRedirection();
 
   // We want ~MessageLoop to happen prior to ~Context. Initializing
   // LazyInstances is akin to stack-allocating objects; their destructors
   // will be invoked first-in-last-out.
   Context* shell_context = new Context();
   shell_context->SetShellFileRoot(base::FilePath(
       base::android::ConvertJavaStringToUTF8(env, j_local_apps_directory)));
   g_context.Get().reset(shell_context);
 
   g_java_message_loop.Get().reset(new base::MessageLoopForUI);
   base::MessageLoopForUI::current()->Start();
 
+  if (trace_startup) {
+    g_java_message_loop.Get()->PostDelayedTask(
+        FROM_HERE,
+        base::Bind(&Tracer::StopAndFlushToFile, base::Unretained(&tracer),

[qsr, 2015/04/08 08:55:57]

I am missing something here. tracer is a stack variable. Your method will end a
few ms after this call. How is this working?

+                   tmp_dir + "/mojo_shell.trace"),
+        base::TimeDelta::FromSeconds(5));
+  }
+
   // TODO(abarth): At which point should we switch to cross-platform
   // initialization?
 
   gfx::GLSurface::InitializeOneOff();
 }
 
 static jboolean Start(JNIEnv* env, jclass clazz) {
   if (!base::CommandLine::ForCurrentProcess()->GetArgs().size())
     return false;
 
@@ skipping 13 matching lines @@
   base::CommandLine::ForCurrentProcess()->AppendArg(
       base::android::ConvertJavaStringToUTF8(env, jurl));
 }
 
 bool RegisterShellMain(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace shell
 }  // namespace mojo