Reland Chrome power profiler service

content/browser/power_profiler/power_profiler_service_unittest.cc

+// Copyright 2014 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 "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "content/browser/browser_thread_impl.h"
+#include "content/browser/power_profiler/power_profiler_service.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace content {
+
+namespace {
+
+const int kNumEvents = 3;
+const int kNumObservers = 3;
+
+// Provide a set number of power events.
+class TestPowerDataProvider : public PowerDataProvider {
+ public:
+  TestPowerDataProvider(int count) : num_events_to_send_(count) {}
+  virtual ~TestPowerDataProvider() {}
+
+  virtual PowerEventVector GetData() OVERRIDE {
+    PowerEventVector events;
+    if (num_events_to_send_ == 0)
+      return events;
+
+    PowerEvent event;
+    event.type = PowerEvent::SOC_PACKAGE;
+    event.time = base::TimeTicks::Now();
+    event.value = 1.0;
+    events.push_back(event);
+
+    num_events_to_send_--;
+    return events;
+  }
+
+ private:
+  int num_events_to_send_;
+  DISALLOW_COPY_AND_ASSIGN(TestPowerDataProvider);
+};
+
+class TestPowerProfilerObserver : public PowerProfilerObserver {
+ public:
+  TestPowerProfilerObserver()
+      : valid_event_count_(0),
+        total_num_events_received_(NULL) {}
+  virtual ~TestPowerProfilerObserver() {}
+
+  virtual void OnPowerEvent(const PowerEventVector& events) OVERRIDE {
+    if (IsValidEvent(events[0])) {
+      ++valid_event_count_;
+      (*total_num_events_received_)++;
+      if (*total_num_events_received_ >= kNumEvents * kNumObservers) {
+        // All expected events received, exiting.
+        base::MessageLoop::current()->Quit();

[Pan, 2014/03/05 10:08:19]

This patch was reverted again due to our test hang on mac_valgrind and
linux_tsan.

I checked the behavior by linux tsan, MessageLoop::current()->Quit() doesn't
work as expected, it never quit the nested loop, (while it works quite well out
of valgrind), interesting.
and I found "Run()" and "Quit()" method in base/message_loop/message_loop.h is
deprecated, in crbug.com/131220, it says Quit leads to Timeout flakiness, while
RunLoop is encouraged to use instead.
So I updated this patch with RunLoop, it passed my local linux tsan and chromium
trybot linux_tsan. 
I think "Quit()" is the same reason for hang on mac_valgrind.

+      }
+    }
+  }
+
+  int valid_event_count() const { return valid_event_count_; }
+
+  void set_total_num_events_received(int* total_num_events_received) {
+    total_num_events_received_ = total_num_events_received;
+  }
+
+ private:
+  bool IsValidEvent(const PowerEvent& event) {
+    return event.type == PowerEvent::SOC_PACKAGE &&
+           !event.time.is_null() &&
+           event.value > 0;
+  }
+
+  int valid_event_count_;
+  int* total_num_events_received_;
+  DISALLOW_COPY_AND_ASSIGN(TestPowerProfilerObserver);
+};
+
+} // namespace
+
+class PowerProfilerServiceTest : public testing::Test {
+ public:
+  void ServiceStartTest() {
+    service_.reset(new PowerProfilerService(
+        make_scoped_ptr<PowerDataProvider>(
+            new TestPowerDataProvider(kNumEvents)),
+        message_loop_.message_loop_proxy(),
+        base::TimeDelta::FromMilliseconds(1)));
+    EXPECT_TRUE(service_->IsAvailable());
+  }
+
+  void AddObserverTest() {
+    for (int index = 0; index < kNumObservers; ++index)
+      service_->AddObserver(&observers_[index]);
+
+    // No PowerEvents received.
+    for (int index = 0; index < kNumObservers; ++index)
+      EXPECT_EQ(observers_[0].valid_event_count(), 0);
+  }
+
+  void RemoveObserverTest() {
+    for (int index = 0; index < kNumObservers; ++index)
+      service_->RemoveObserver(&observers_[index]);
+
+    // Everyone received |kNumEvents| events.
+    for (int index = 0; index < kNumObservers; ++index)
+      EXPECT_EQ(observers_[index].valid_event_count(), kNumEvents);
+  }
+
+ protected:
+  PowerProfilerServiceTest()
+      : ui_thread_(BrowserThread::UI, &message_loop_),
+        total_num_events_received(0) {
+    for (int index = 0; index < kNumObservers; ++index) {
+      observers_[index].set_total_num_events_received(
+          &total_num_events_received);
+    }
+  }
+  virtual ~PowerProfilerServiceTest() {}
+
+ private:
+  scoped_ptr<PowerProfilerService> service_;
+  TestPowerProfilerObserver observers_[kNumObservers];
+
+  // UI thread.
+  base::MessageLoopForUI message_loop_;
+  BrowserThreadImpl ui_thread_;
+
+  int total_num_events_received;
+
+  DISALLOW_COPY_AND_ASSIGN(PowerProfilerServiceTest);
+};
+
+// Test whether PowerProfilerService dispatches power events to observers
+// properly.
+TEST_F(PowerProfilerServiceTest, AvailableService) {
+  ServiceStartTest();
+  AddObserverTest();
+  base::MessageLoop::current()->Run();
+  RemoveObserverTest();
+}
+
+}  // namespace content