Add a task_scheduler tracing category which will record an extra event per task.

base/sequence_token_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/sequence_token.h"
 
+#include "base/strings/string_number_conversions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 
 TEST(SequenceTokenTest, IsValid) {
   EXPECT_FALSE(SequenceToken().IsValid());
   EXPECT_TRUE(SequenceToken::Create().IsValid());
 }
 
 TEST(SequenceTokenTest, OperatorEquals) {
@@ skipping 38 matching lines @@
   {
     ScopedSetSequenceTokenForCurrentThread
         scoped_set_sequence_token_for_current_thread(token);
     EXPECT_TRUE(SequenceToken::GetForCurrentThread().IsValid());
     EXPECT_EQ(token, SequenceToken::GetForCurrentThread());
   }
 
   EXPECT_FALSE(SequenceToken::GetForCurrentThread().IsValid());
 }
 
+TEST(SequenceTokenTest, ToString) {
+  const SequenceToken token1 = SequenceToken::Create();
+  const SequenceToken token2 = SequenceToken::Create();
+
+  const std::string token1_str = token1.ToString();
+  const std::string token2_str = token2.ToString();
+
+  // Confirm that the strings are numerical representations.
+  int token1_int = -1;
+  int token2_int = -1;
+  EXPECT_TRUE(StringToInt(token1_str, &token1_int));
+  EXPECT_TRUE(StringToInt(token2_str, &token2_int));
+
+  // Confirm that they are unique.
+  EXPECT_NE(token1_str, token2_str);
+  EXPECT_NE(token1_int, token2_int);
+}
+
 // Expect a default-constructed TaskToken to be invalid and not equal to
 // another invalid TaskToken.
 TEST(TaskTokenTest, InvalidDefaultConstructed) {
   EXPECT_FALSE(TaskToken().IsValid());
   EXPECT_NE(TaskToken(), TaskToken());
 }
 
 // Expect a TaskToken returned by TaskToken::GetForCurrentThread() outside the
 // scope of a ScopedSetSequenceTokenForCurrentThread to be invalid.
 TEST(TaskTokenTest, InvalidOutsideScope) {
@@ skipping 41 matching lines @@
         scoped_set_sequence_token_for_current_thread(SequenceToken::Create());
     token_b = TaskToken::GetForCurrentThread();
   }
 
   EXPECT_TRUE(token_a.IsValid());
   EXPECT_TRUE(token_b.IsValid());
   EXPECT_NE(token_a, token_b);
 }
 
 }  // namespace base