[memory-infra] Move periodic timer to dump thread

base/trace_event/memory_dump_scheduler.cc

Index: base/trace_event/memory_dump_scheduler.cc
diff --git a/base/trace_event/memory_dump_scheduler.cc b/base/trace_event/memory_dump_scheduler.cc
index 66ea6c9f1aeb5dd98b8af1ac43d11a26b0d025be..9f34f948394900fc3079cfd278231a7f6b3f6ccc 100644
--- a/base/trace_event/memory_dump_scheduler.cc
+++ b/base/trace_event/memory_dump_scheduler.cc
@@ -22,6 +22,9 @@ uint32_t g_polling_interval_ms_for_testing = 0;
 }  // namespace
 
 // static
+bool MemoryDumpScheduler::periodic_timer_disabled_for_testing_ = false;
+
+// static
 MemoryDumpScheduler* MemoryDumpScheduler::GetInstance() {
   static MemoryDumpScheduler* instance = new MemoryDumpScheduler();
   return instance;
@@ -88,8 +91,17 @@ void MemoryDumpScheduler::EnablePeriodicTriggerIfNeeded() {
                                       periodic_state_->min_timer_period_ms;
   periodic_state_->heavy_dumps_rate = periodic_state_->heavy_dump_period_ms /
                                       periodic_state_->min_timer_period_ms;
-
   periodic_state_->dump_count = 0;
+  periodic_state_->is_enabled_for_testing = true;
+
+  if (periodic_timer_disabled_for_testing_)
+    return;
+  polling_task_runner_->PostTask(
+      FROM_HERE, Bind(&MemoryDumpScheduler::EnablePeriodicTimerOnPollingThread,
+                      Unretained(this)));
+}
+
+void MemoryDumpScheduler::EnablePeriodicTimerOnPollingThread() {
   periodic_state_->timer.Start(
       FROM_HERE,
       TimeDelta::FromMilliseconds(periodic_state_->min_timer_period_ms),
@@ -127,23 +139,22 @@ void MemoryDumpScheduler::NotifyDumpTriggered() {
 }
 
 void MemoryDumpScheduler::DisableAllTriggers() {
-  if (periodic_state_) {
-    if (periodic_state_->timer.IsRunning())
-      periodic_state_->timer.Stop();
-    periodic_state_.reset();
-  }
-
   if (polling_task_runner_) {
-    DCHECK(polling_state_);
     polling_task_runner_->PostTask(
-        FROM_HERE, Bind(&MemoryDumpScheduler::DisablePollingOnPollingThread,
+        FROM_HERE, Bind(&MemoryDumpScheduler::DisableTriggersOnPollingThread,
                         Unretained(this)));
     polling_task_runner_ = nullptr;
   }
   is_setup_ = false;
 }
 
-void MemoryDumpScheduler::DisablePollingOnPollingThread() {
+void MemoryDumpScheduler::DisableTriggersOnPollingThread() {
+  if (periodic_state_) {
+    if (periodic_state_->timer.IsRunning())
+      periodic_state_->timer.Stop();
+    periodic_state_.reset();
+  }
+
   polling_state_->current_state = PollingTriggerState::DISABLED;
   polling_state_.reset();
 }
@@ -153,11 +164,19 @@ void MemoryDumpScheduler::SetPollingIntervalForTesting(uint32_t interval) {
   g_polling_interval_ms_for_testing = interval;
 }
 
+void MemoryDumpScheduler::DisablePeriodicTimerForTesting(bool disable) {
+  periodic_timer_disabled_for_testing_ = disable;
+}
+
 bool MemoryDumpScheduler::IsPeriodicTimerRunningForTesting() {
-  return periodic_state_->timer.IsRunning();
+  return periodic_state_->is_enabled_for_testing;
 }
 
 void MemoryDumpScheduler::RequestPeriodicGlobalDump() {
+  // In case it's called after timer stopped.
+  if (!periodic_state_)
+    return;
+
   MemoryDumpLevelOfDetail level_of_detail = MemoryDumpLevelOfDetail::BACKGROUND;
   if (periodic_state_->light_dumps_rate > 0 &&
       periodic_state_->dump_count % periodic_state_->light_dumps_rate == 0)
@@ -171,7 +190,7 @@ void MemoryDumpScheduler::RequestPeriodicGlobalDump() {
 }
 
 void MemoryDumpScheduler::PollMemoryOnPollingThread() {
-  if (polling_state_->current_state != PollingTriggerState::ENABLED)
+  if (!polling_state_)
     return;
 
   uint64_t polled_memory = 0;
@@ -273,7 +292,8 @@ MemoryDumpScheduler::PeriodicTriggerState::PeriodicTriggerState()
       light_dumps_rate(0),
       heavy_dumps_rate(0),
       light_dump_period_ms(0),
-      heavy_dump_period_ms(0) {}
+      heavy_dump_period_ms(0),
+      is_enabled_for_testing(false) {}
 
 MemoryDumpScheduler::PeriodicTriggerState::~PeriodicTriggerState() {
   DCHECK(!timer.IsRunning());