TaskScheduler: Avoid Sequence refcount bump in GetWork()

base/task_scheduler/sequence_sort_key_unittest.cc

 // Copyright 2016 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/task_scheduler/sequence_sort_key.h"
 
 #include "base/task_scheduler/task_traits.h"
 #include "base/time/time.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 107 matching lines @@
   EXPECT_FALSE(key_f > key_e);
 
   EXPECT_GT(key_a, key_f);
   EXPECT_GT(key_b, key_f);
   EXPECT_GT(key_c, key_f);
   EXPECT_GT(key_d, key_f);
   EXPECT_GT(key_e, key_f);
   EXPECT_FALSE(key_f > key_f);
 }
 
+TEST(TaskSchedulerSequenceSortKeyTest, OperatorEqualAndNotEqual) {
+  SequenceSortKey key_a(TaskPriority::USER_BLOCKING,
+                        TimeTicks::FromInternalValue(1000));
+  SequenceSortKey key_b(TaskPriority::USER_BLOCKING,
+                        TimeTicks::FromInternalValue(2000));
+  SequenceSortKey key_c(TaskPriority::USER_VISIBLE,
+                        TimeTicks::FromInternalValue(1000));
+  SequenceSortKey key_d(TaskPriority::USER_VISIBLE,
+                        TimeTicks::FromInternalValue(2000));
+  SequenceSortKey key_e(TaskPriority::BACKGROUND,
+                        TimeTicks::FromInternalValue(1000));
+  SequenceSortKey key_f(TaskPriority::BACKGROUND,
+                        TimeTicks::FromInternalValue(2000));
+
+  EXPECT_EQ(key_a, key_a);

[fdoray, 2016/04/28 14:32:29]

This test will succeed if operator== and operator!= always return true. You
should test operator== and operator!= separately.

TEST(... OperatorEqual) {
  EXPECT_EQ(key_a, key_a);
  EXPECT_FALSE(key_b == key_a);
  ...
}

TEST(..., OperatorNotEqual) {
  EXPECT_FALSE(key_a != key_a); 
  EXPECT_NE(key_b, key_a);
  ...
}

[gab, 2016/04/28 15:36:55]

Good catch, done :-)

+  EXPECT_NE(key_b, key_a);
+  EXPECT_NE(key_c, key_a);
+  EXPECT_NE(key_d, key_a);
+  EXPECT_NE(key_e, key_a);
+  EXPECT_NE(key_f, key_a);
+
+  EXPECT_NE(key_a, key_b);
+  EXPECT_EQ(key_b, key_b);
+  EXPECT_NE(key_c, key_b);
+  EXPECT_NE(key_d, key_b);
+  EXPECT_NE(key_e, key_b);
+  EXPECT_NE(key_f, key_b);
+
+  EXPECT_NE(key_a, key_c);
+  EXPECT_NE(key_b, key_c);
+  EXPECT_EQ(key_c, key_c);
+  EXPECT_NE(key_d, key_c);
+  EXPECT_NE(key_e, key_c);
+  EXPECT_NE(key_f, key_c);
+
+  EXPECT_NE(key_a, key_d);
+  EXPECT_NE(key_b, key_d);
+  EXPECT_NE(key_c, key_d);
+  EXPECT_EQ(key_d, key_d);
+  EXPECT_NE(key_e, key_d);
+  EXPECT_NE(key_f, key_d);
+
+  EXPECT_NE(key_a, key_e);
+  EXPECT_NE(key_b, key_e);
+  EXPECT_NE(key_c, key_e);
+  EXPECT_NE(key_d, key_e);
+  EXPECT_EQ(key_e, key_e);
+  EXPECT_NE(key_f, key_e);
+
+  EXPECT_NE(key_a, key_f);
+  EXPECT_NE(key_b, key_f);
+  EXPECT_NE(key_c, key_f);
+  EXPECT_NE(key_d, key_f);
+  EXPECT_NE(key_e, key_f);
+  EXPECT_EQ(key_f, key_f);
+}
+
 }  // namespace internal
 }  // namespace base