Support parallel captures from the StackSamplingProfiler.

base/profiler/stack_sampling_profiler_unittest.cc

Index: base/profiler/stack_sampling_profiler_unittest.cc
diff --git a/base/profiler/stack_sampling_profiler_unittest.cc b/base/profiler/stack_sampling_profiler_unittest.cc
index 16205ac2b09f22e25975cda252c8306ba6eb918a..a9b3cef246cc56e6ef49735da0c316a0627707bb 100644
--- a/base/profiler/stack_sampling_profiler_unittest.cc
+++ b/base/profiler/stack_sampling_profiler_unittest.cc
@@ -444,9 +444,9 @@ void TestLibraryUnload(bool wait_until_unloaded) {
     StackCopiedSignaler(WaitableEvent* stack_copied,
                         WaitableEvent* start_stack_walk,
                         bool wait_to_walk_stack)
-        : stack_copied_(stack_copied), start_stack_walk_(start_stack_walk),
-          wait_to_walk_stack_(wait_to_walk_stack) {
-    }
+        : stack_copied_(stack_copied),
+          start_stack_walk_(start_stack_walk),
+          wait_to_walk_stack_(wait_to_walk_stack) {}
 
     void OnPreStackWalk() override {
       stack_copied_->Signal();
@@ -623,6 +623,18 @@ TEST(StackSamplingProfilerTest, MAYBE_Basic) {
   FilePath executable_path;
   EXPECT_TRUE(PathService::Get(FILE_EXE, &executable_path));
   EXPECT_EQ(executable_path, profile.modules[loc->module_index].filename);
+
+  // Ensure the sampling thread is still running at this point.
+  ASSERT_TRUE(StackSamplingProfiler::IsSamplingThreadRunningForTesting());
+
+  // Shutdown the sampler as though the process were about to exit.
+  StackSamplingProfiler::Shutdown();
+  EXPECT_FALSE(StackSamplingProfiler::IsSamplingThreadRunningForTesting());
+
+  // Shutdown is a permanent thing in general but this needs to be undone so
+  // other tests can run.
+  StackSamplingProfiler::UndoShutdownForTesting();
+  EXPECT_FALSE(StackSamplingProfiler::IsSamplingThreadRunningForTesting());
 }
 
 // Checks that annotations are recorded in samples.
@@ -720,35 +732,6 @@ TEST(StackSamplingProfilerTest, MAYBE_Alloca) {
       << FormatSampleForDiagnosticOutput(sample, profile.modules);
 }
 
-// Checks that the fire-and-forget interface works.
-#if defined(STACK_SAMPLING_PROFILER_SUPPORTED)
-#define MAYBE_StartAndRunAsync StartAndRunAsync
-#else
-#define MAYBE_StartAndRunAsync DISABLED_StartAndRunAsync
-#endif
-TEST(StackSamplingProfilerTest, MAYBE_StartAndRunAsync) {
-  // StartAndRunAsync requires the caller to have a message loop.
-  MessageLoop message_loop;
-
-  SamplingParams params;
-  params.samples_per_burst = 1;
-
-  CallStackProfiles profiles;
-  WithTargetThread([&params, &profiles](PlatformThreadId target_thread_id) {
-    WaitableEvent sampling_thread_completed(
-        WaitableEvent::ResetPolicy::AUTOMATIC,
-        WaitableEvent::InitialState::NOT_SIGNALED);
-    const StackSamplingProfiler::CompletedCallback callback =
-        Bind(&SaveProfilesAndSignalEvent, Unretained(&profiles),
-             Unretained(&sampling_thread_completed));
-    StackSamplingProfiler::StartAndRunAsync(target_thread_id, params, callback);
-    RunLoop().RunUntilIdle();
-    sampling_thread_completed.Wait();
-  });
-
-  ASSERT_EQ(1u, profiles.size());
-}
-
 // Checks that the expected number of profiles and samples are present in the
 // call stack profiles produced.
 #if defined(STACK_SAMPLING_PROFILER_SUPPORTED)
@@ -860,6 +843,8 @@ TEST(StackSamplingProfilerTest, MAYBE_DestroyProfilerWhileProfiling) {
 #define MAYBE_CanRunMultipleTimes DISABLED_CanRunMultipleTimes
 #endif
 TEST(StackSamplingProfilerTest, MAYBE_CanRunMultipleTimes) {
+  StackSamplingProfiler::SetSamplingThreadIdleShutdownTimeForTesting(0);
+
   SamplingParams params;
   params.sampling_interval = TimeDelta::FromMilliseconds(0);
   params.samples_per_burst = 1;
@@ -871,10 +856,24 @@ TEST(StackSamplingProfilerTest, MAYBE_CanRunMultipleTimes) {
   profiles.clear();
   CaptureProfiles(params, AVeryLongTimeDelta(), &profiles);
   ASSERT_EQ(1u, profiles.size());
+
+  // Capture thread should still be running at this point.
+  ASSERT_TRUE(StackSamplingProfiler::IsSamplingThreadRunningForTesting());
+
+  // Initiate an "idle" shutdown.  The task will be run immediately but on
+  // another thread so wait for it to complete.
+  StackSamplingProfiler::InitiateSamplingThreadIdleShutdownForTesting();
+  while (StackSamplingProfiler::IsSamplingThreadRunningForTesting())
+    PlatformThread::YieldCurrentThread();
+
+  // Ensure another capture will start the sampling thread and run.
+  profiles.clear();
+  CaptureProfiles(params, AVeryLongTimeDelta(), &profiles);
+  ASSERT_EQ(1u, profiles.size());
+  EXPECT_TRUE(StackSamplingProfiler::IsSamplingThreadRunningForTesting());
 }
 
-// Checks that requests to start profiling while another profile is taking place
-// are ignored.
+// Checks that multiple sampling requests execute in parallel.
 #if defined(STACK_SAMPLING_PROFILER_SUPPORTED)
 #define MAYBE_ConcurrentProfiling ConcurrentProfiling
 #else
@@ -884,11 +883,12 @@ TEST(StackSamplingProfilerTest, MAYBE_ConcurrentProfiling) {
   WithTargetThread([](PlatformThreadId target_thread_id) {
     SamplingParams params[2];
     params[0].initial_delay = TimeDelta::FromMilliseconds(10);
-    params[0].sampling_interval = TimeDelta::FromMilliseconds(0);
-    params[0].samples_per_burst = 1;
+    params[0].sampling_interval = TimeDelta::FromMilliseconds(1);
+    params[0].samples_per_burst = 10;
 
-    params[1].sampling_interval = TimeDelta::FromMilliseconds(0);
-    params[1].samples_per_burst = 1;
+    params[0].initial_delay = TimeDelta::FromMilliseconds(10);
+    params[1].sampling_interval = TimeDelta::FromMilliseconds(1);
+    params[1].samples_per_burst = 10;
 
     CallStackProfiles profiles[2];
     std::vector<std::unique_ptr<WaitableEvent>> sampling_completed(2);
@@ -919,14 +919,9 @@ TEST(StackSamplingProfilerTest, MAYBE_ConcurrentProfiling) {
     EXPECT_EQ(1u, profiles[completed_profiler].size());
 
     size_t other_profiler = 1 - completed_profiler;
-    // Give the other profiler a chance to run and observe that it hasn't.
-    EXPECT_FALSE(sampling_completed[other_profiler]->TimedWait(
-        TimeDelta::FromMilliseconds(25)));
-
-    // Start the other profiler again and it should run.
-    profiler[other_profiler]->Start();
-    sampling_completed[other_profiler]->Wait();
-    EXPECT_EQ(1u, profiles[other_profiler].size());
+    // Give the other profiler a chance to finish and verify it does so.
+    EXPECT_TRUE(sampling_completed[other_profiler]->TimedWait(
+        TimeDelta::FromMilliseconds(250)));
   });
 }