[Mac] Reduce timer CPU use in MessagePumpCFRunLoopBase.

base/message_loop/message_pump_mac_unittest.cc

Index: base/message_loop/message_pump_mac_unittest.cc
diff --git a/base/message_loop/message_pump_mac_unittest.cc b/base/message_loop/message_pump_mac_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..17c70c8a6cbe32e577a10c035d87d74fb9e5aadf
--- /dev/null
+++ b/base/message_loop/message_pump_mac_unittest.cc
@@ -0,0 +1,108 @@
+// Copyright 2017 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_pump_mac.h"
+
+#include "base/mac/scoped_cftyperef.h"
+#include "base/macros.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+class TestMessagePumpCFRunLoopBase {
+ public:
+  bool TestCanInvalidateTimers() {
+    return MessagePumpCFRunLoopBase::CanInvalidateCFRunLoopTimers();
+  }
+  static void SetTimerValid(CFRunLoopTimerRef timer, bool valid) {
+    MessagePumpCFRunLoopBase::ChromeCFRunLoopTimerSetValid(timer, valid);
+  }
+
+  static void PerformTimerCallback(CFRunLoopTimerRef timer, void* info) {
+    TestMessagePumpCFRunLoopBase* self =
+        static_cast<TestMessagePumpCFRunLoopBase*>(info);
+    self->timer_callback_called_ = true;
+
+    if (self->invalidate_timer_in_callback_) {
+      SetTimerValid(timer, false);
+    }
+  }
+
+  bool invalidate_timer_in_callback_;
+
+  bool timer_callback_called_;
+};
+
+TEST(MessagePumpMacTest, TestCanInvalidateTimers) {
+  TestMessagePumpCFRunLoopBase message_pump_test;
+
+  // Catch whether or not the use of private API ever starts failing.
+  EXPECT_TRUE(message_pump_test.TestCanInvalidateTimers());
+}
+
+TEST(MessagePumpMacTest, TestInvalidatedTimerReuse) {
+  TestMessagePumpCFRunLoopBase message_pump_test;
+
+  CFRunLoopTimerContext timer_context = CFRunLoopTimerContext();
+  timer_context.info = &message_pump_test;
+  const CFTimeInterval kCFTimeIntervalMax =
+      std::numeric_limits<CFTimeInterval>::max();
+  ScopedCFTypeRef<CFRunLoopTimerRef> test_timer(CFRunLoopTimerCreate(
+      NULL,                // allocator
+      kCFTimeIntervalMax,  // fire time
+      kCFTimeIntervalMax,  // interval
+      0,                   // flags
+      0,                   // priority
+      TestMessagePumpCFRunLoopBase::PerformTimerCallback, &timer_context));
+  CFRunLoopAddTimer(CFRunLoopGetCurrent(), test_timer,
+                    kMessageLoopExclusiveRunLoopMode);
+
+  // Sanity check.
+  EXPECT_TRUE(CFRunLoopTimerIsValid(test_timer));
+
+  // Confirm that the timer fires as expected, and that it's not a one-time-use
+  // timer (those timers are invalidated after they fire).
+  CFAbsoluteTime next_fire_time = CFAbsoluteTimeGetCurrent() + 0.01;
+  CFRunLoopTimerSetNextFireDate(test_timer, next_fire_time);
+  message_pump_test.timer_callback_called_ = false;
+  message_pump_test.invalidate_timer_in_callback_ = false;
+  CFRunLoopRunInMode(kMessageLoopExclusiveRunLoopMode, 0.02, true);
+  EXPECT_TRUE(message_pump_test.timer_callback_called_);
+  EXPECT_TRUE(CFRunLoopTimerIsValid(test_timer));
+
+  // As a repeating timer, the timer should have a new fire date set in the
+  // future.
+  EXPECT_GT(CFRunLoopTimerGetNextFireDate(test_timer), next_fire_time);
+
+  // Try firing the timer, and invalidating it within its callback.
+  next_fire_time = CFAbsoluteTimeGetCurrent() + 0.01;
+  CFRunLoopTimerSetNextFireDate(test_timer, next_fire_time);
+  message_pump_test.timer_callback_called_ = false;
+  message_pump_test.invalidate_timer_in_callback_ = true;
+  CFRunLoopRunInMode(kMessageLoopExclusiveRunLoopMode, 0.02, true);
+  EXPECT_TRUE(message_pump_test.timer_callback_called_);
+  EXPECT_FALSE(CFRunLoopTimerIsValid(test_timer));
+
+  // The CFRunLoop believes the timer is invalid, so it should not have a
+  // fire date.
+  EXPECT_EQ(0, CFRunLoopTimerGetNextFireDate(test_timer));
+
+  // Now mark the timer as valid and confirm that it still fires correctly.
+  TestMessagePumpCFRunLoopBase::SetTimerValid(test_timer, true);
+  EXPECT_TRUE(CFRunLoopTimerIsValid(test_timer));
+  next_fire_time = CFAbsoluteTimeGetCurrent() + 0.01;
+  CFRunLoopTimerSetNextFireDate(test_timer, next_fire_time);
+  message_pump_test.timer_callback_called_ = false;
+  message_pump_test.invalidate_timer_in_callback_ = false;
+  CFRunLoopRunInMode(kMessageLoopExclusiveRunLoopMode, 0.02, true);
+  EXPECT_TRUE(message_pump_test.timer_callback_called_);
+  EXPECT_TRUE(CFRunLoopTimerIsValid(test_timer));
+
+  // Confirm that the run loop again gave it a new fire date in the future.
+  EXPECT_GT(CFRunLoopTimerGetNextFireDate(test_timer), next_fire_time);
+
+  CFRunLoopRemoveTimer(CFRunLoopGetCurrent(), test_timer,
+                       kMessageLoopExclusiveRunLoopMode);
+}
+}  // namespace base