Reduce the number of threads created by the load TaskTracker tests.

base/task_scheduler/task_tracker_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/task_tracker.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
@@ skipping 25 matching lines @@
 #include "base/threading/simple_thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 namespace internal {
 
 namespace {
 
-constexpr size_t kLoadTestNumIterations = 100;
+constexpr size_t kLoadTestNumIterations = 75;
 
 // Invokes a closure asynchronously.
 class CallbackThread : public SimpleThread {
  public:
   explicit CallbackThread(const Closure& closure)
       : SimpleThread("CallbackThread"), closure_(closure) {}
 
   // Returns true once the callback returns.
   bool has_returned() { return has_returned_.IsSet(); }
 
@@ skipping 886 matching lines @@
     ASSERT_TRUE(tracker.WillPostTask(task.get()));
 
     HistogramTester tester;
     EXPECT_TRUE(tracker.RunTask(std::move(task), SequenceToken::Create()));
     tester.ExpectTotalCount(test.expected_histogram, 1);
   }
 }
 
 }  // namespace internal
 }  // namespace base