ThreadWatcher: fixes Start/StopWatchingAll.

chrome/browser/metrics/thread_watcher_unittest.cc

Index: chrome/browser/metrics/thread_watcher_unittest.cc
diff --git a/chrome/browser/metrics/thread_watcher_unittest.cc b/chrome/browser/metrics/thread_watcher_unittest.cc
index 4b799e9c07f051ba64a18869e5625706d8f834bd..7efb041acdc723de82390884ed4f53c91a1a70b7 100644
--- a/chrome/browser/metrics/thread_watcher_unittest.cc
+++ b/chrome/browser/metrics/thread_watcher_unittest.cc
@@ -10,6 +10,7 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
+#include "base/run_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_tokenizer.h"
@@ -629,3 +630,53 @@ TEST_F(ThreadWatcherTest, MultipleThreadsNotResponding) {
   // Wait for the io_watcher_'s VeryLongMethod to finish.
   io_watcher_->WaitForWaitStateChange(kUnresponsiveTime * 10, ALL_DONE);
 }
+
+TEST(ThreadWatcherListTest, Restart) {
+  ThreadWatcherList::g_initialize_delay_seconds = 1;
+
+  base::MessageLoopForUI message_loop_for_ui;
+  content::TestBrowserThread ui_thread(BrowserThread::UI, &message_loop_for_ui);
+
+  scoped_ptr<WatchDogThread> watchdog_thread_(new WatchDogThread());
+  watchdog_thread_->Start();
+
+  EXPECT_FALSE(ThreadWatcherList::g_thread_watcher_list_);
+
+  // See http://crbug.com/347887.
+  // StartWatchingAll() will PostDelayedTask to create g_thread_watcher_list_,
+  // whilst StopWatchingAll() will just PostTask to destroy it.
+  // Ensure that when Stop is called, Start will NOT create
+  // g_thread_watcher_list_ later on.
+  ThreadWatcherList::StartWatchingAll(*CommandLine::ForCurrentProcess());
+  ThreadWatcherList::StopWatchingAll();
+  message_loop_for_ui.PostDelayedTask(
+      FROM_HERE,
+      message_loop_for_ui.QuitClosure(),
+      base::TimeDelta::FromSeconds(
+          ThreadWatcherList::g_initialize_delay_seconds));
+  message_loop_for_ui.Run();
+  EXPECT_FALSE(ThreadWatcherList::g_thread_watcher_list_);
+  EXPECT_TRUE(ThreadWatcherList::g_stopped_);
+
+  // Proceed with just |StartWatchingAll| and ensure it'll be started.
+  ThreadWatcherList::StartWatchingAll(*CommandLine::ForCurrentProcess());
+  message_loop_for_ui.PostDelayedTask(
+      FROM_HERE,
+      message_loop_for_ui.QuitClosure(),
+      base::TimeDelta::FromSeconds(
+          ThreadWatcherList::g_initialize_delay_seconds + 1));
+  message_loop_for_ui.Run();
+  EXPECT_TRUE(ThreadWatcherList::g_thread_watcher_list_);
+  EXPECT_FALSE(ThreadWatcherList::g_stopped_);
+
+  // Finally, StopWatchingAll() must stop.
+  ThreadWatcherList::StopWatchingAll();
+  message_loop_for_ui.PostDelayedTask(
+      FROM_HERE,
+      message_loop_for_ui.QuitClosure(),
+      base::TimeDelta::FromSeconds(
+          ThreadWatcherList::g_initialize_delay_seconds));
+  message_loop_for_ui.Run();
+  EXPECT_FALSE(ThreadWatcherList::g_thread_watcher_list_);
+  EXPECT_TRUE(ThreadWatcherList::g_stopped_);
+}