[memory-infra] Make MemoryDumpScheduler non-thread safe singleton

base/trace_event/memory_dump_scheduler_unittest.cc

 // 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/trace_event/memory_dump_scheduler.h"
 
 #include <memory>
 
 #include "base/single_thread_task_runner.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 namespace trace_event {
 
 class MemoryDumpSchedulerPollingTest : public testing::Test {
  public:
   static const uint32_t kMinPollsToDump = 5;
 
   MemoryDumpSchedulerPollingTest()
       : testing::Test(),
         num_samples_tracked_(
             MemoryDumpScheduler::PollingTriggerState::kMaxNumMemorySamples) {}
 
   void SetUp() override {
     MemoryDumpScheduler::SetPollingIntervalForTesting(1);
     uint32_t kMinPollsToDump = 5;
-    mds_.reset(new MemoryDumpScheduler(nullptr, nullptr));
+    mds_ = MemoryDumpScheduler::GetInstance();
+    mds_->Setup(nullptr, nullptr);
     mds_->AddTrigger(MemoryDumpType::PEAK_MEMORY_USAGE,
                      MemoryDumpLevelOfDetail::LIGHT, kMinPollsToDump);
-    mds_->polling_state_.ResetTotals();
-    mds_->polling_state_.current_state =
+    mds_->polling_state_->ResetTotals();
+    mds_->polling_state_->current_state =
         MemoryDumpScheduler::PollingTriggerState::ENABLED;
   }
 
   void TearDown() override {
-    mds_->polling_state_.current_state =
+    mds_->polling_state_->current_state =
         MemoryDumpScheduler::PollingTriggerState::DISABLED;
-    mds_.reset();
   }
 
  protected:
   bool ShouldTriggerDump(uint64_t total) {
     return mds_->ShouldTriggerDump(total);
   }
 
   uint32_t num_samples_tracked_;
-  std::unique_ptr<MemoryDumpScheduler> mds_;
+  MemoryDumpScheduler* mds_;
 };
 
 TEST_F(MemoryDumpSchedulerPollingTest, PeakDetection) {
   for (uint32_t i = 0; i < num_samples_tracked_ * 6; ++i) {
     // Memory is increased in steps and dumps must be triggered at every step.
     uint64_t total = (2 + (i / (2 * num_samples_tracked_))) * 1024 * 1204;
     bool did_trigger = ShouldTriggerDump(total);
     // Dumps must be triggered only at specific iterations.
     bool should_have_triggered = i == 0;
     should_have_triggered |=
@@ skipping 22 matching lines @@
 }
 
 TEST_F(MemoryDumpSchedulerPollingTest, NotifyDumpTriggered) {
   for (uint32_t i = 0; i < num_samples_tracked_ * 6; ++i) {
     uint64_t total = (2 + (i / (2 * num_samples_tracked_))) * 1024 * 1204;
     if (i % num_samples_tracked_ == 0)
       mds_->NotifyDumpTriggered();
     bool did_trigger = ShouldTriggerDump(total);
     // Dumps should never be triggered since NotifyDumpTriggered() is called
     // frequently.
-    EXPECT_NE(0u, mds_->polling_state_.last_dump_memory_total);
+    EXPECT_NE(0u, mds_->polling_state_->last_dump_memory_total);
     EXPECT_GT(num_samples_tracked_ - 1,
-              mds_->polling_state_.last_memory_totals_kb_index);
-    EXPECT_LT(static_cast<int64_t>(total -
-                                   mds_->polling_state_.last_dump_memory_total),
-              mds_->polling_state_.memory_increase_threshold);
+              mds_->polling_state_->last_memory_totals_kb_index);
+    EXPECT_LT(static_cast<int64_t>(
+                  total - mds_->polling_state_->last_dump_memory_total),
+              mds_->polling_state_->memory_increase_threshold);
     ASSERT_FALSE(did_trigger && i) << "Unexpected dump at " << i;
   }
 }
 
 }  // namespace trace_event
 }  // namespace base