[runtime-call-stats] Fix the threading check in debug mode.

The RuntimeCallStats object happen to be created on the main thread,
but then got used in a worker. Make sure the thread checks do not
fire false positives in this case.

BUG=chromium:760649

Change-Id: I8f2a2b4d1da1bc48416987ea378688ec15b9d955
Reviewed-on: https://chromium-review.googlesource.com/706181Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48409}

src/counters.cc

@@ -420,8 +420,7 @@ void RuntimeCallTimer::Snapshot() {
   Resume(now);
 }
 
-RuntimeCallStats::RuntimeCallStats()
-    : in_use_(false), thread_id_(ThreadId::Current()) {
+RuntimeCallStats::RuntimeCallStats() : in_use_(false) {
   static const char* const kNames[] = {
 #define CALL_BUILTIN_COUNTER(name) "GC_" #name,
       FOR_EACH_GC_COUNTER(CALL_BUILTIN_COUNTER)  //
@@ -477,7 +476,7 @@ const int RuntimeCallStats::counters_count =
 // static
 void RuntimeCallStats::Enter(RuntimeCallStats* stats, RuntimeCallTimer* timer,
                              CounterId counter_id) {
-  DCHECK(ThreadId::Current().Equals(stats->thread_id()));
+  DCHECK(stats->IsCalledOnTheSameThread());
   RuntimeCallCounter* counter = &(stats->*counter_id);
   DCHECK(counter->name() != nullptr);
   timer->Start(counter, stats->current_timer_.Value());
@@ -487,7 +486,7 @@ void RuntimeCallStats::Enter(RuntimeCallStats* stats, RuntimeCallTimer* timer,
 
 // static
 void RuntimeCallStats::Leave(RuntimeCallStats* stats, RuntimeCallTimer* timer) {
-  DCHECK(ThreadId::Current().Equals(stats->thread_id()));
+  DCHECK(stats->IsCalledOnTheSameThread());
   if (stats->current_timer_.Value() != timer) {
     // The branch is added to catch a crash crbug.com/760649
     EmbeddedVector<char, 200> text;
@@ -521,6 +520,13 @@ void RuntimeCallStats::CorrectCurrentCounterId(RuntimeCallStats* stats,
   stats->current_counter_.SetValue(counter);
 }
 
+bool RuntimeCallStats::IsCalledOnTheSameThread() {
+  if (!thread_id_.Equals(ThreadId::Invalid()))
+    return thread_id_.Equals(ThreadId::Current());
+  thread_id_ = ThreadId::Current();
+  return true;
+}
+
 void RuntimeCallStats::Print(std::ostream& os) {
   RuntimeCallStatEntries entries;
   if (current_timer_.Value() != nullptr) {

src/counters.h

@@ -937,6 +937,7 @@ class RuntimeCallStats final : public ZoneObject {
   RuntimeCallTimer* current_timer() { return current_timer_.Value(); }
   RuntimeCallCounter* current_counter() { return current_counter_.Value(); }
   bool InUse() { return in_use_; }
+  bool IsCalledOnTheSameThread();
 
  private:
   // Top of a stack of active timers.