1 files changed, 20 insertions, 16 deletions

diff --git a/deps/v8/src/counters.cc b/deps/v8/src/counters.cc
index a5709dbec9..c754e6fdef 100644
--- a/deps/v8/src/counters.cc
+++ b/deps/v8/src/counters.cc
@@ -16,9 +16,9 @@ namespace v8 {
 namespace internal {
 
 StatsTable::StatsTable(Counters* counters)
-    : lookup_function_(NULL),
-      create_histogram_function_(NULL),
-      add_histogram_sample_function_(NULL) {}
+    : lookup_function_(nullptr),
+      create_histogram_function_(nullptr),
+      add_histogram_sample_function_(nullptr) {}
 
 void StatsTable::SetCounterFunction(CounterLookupCallback f) {
   lookup_function_ = f;
@@ -313,6 +313,9 @@ void Counters::ResetCreateHistogramFunction(CreateHistogramCallback f) {
 #undef HM
 }
 
+base::TimeTicks (*RuntimeCallTimer::Now)() =
+    &base::TimeTicks::HighResolutionNow;
+
 class RuntimeCallStatEntries {
  public:
   void Print(std::ostream& os) {
@@ -478,8 +481,8 @@ void RuntimeCallStats::Enter(RuntimeCallStats* stats, RuntimeCallTimer* timer,
                              CounterId counter_id) {
   DCHECK(stats->IsCalledOnTheSameThread());
   RuntimeCallCounter* counter = &(stats->*counter_id);
-  DCHECK(counter->name() != nullptr);
-  timer->Start(counter, stats->current_timer_.Value());
+  DCHECK_NOT_NULL(counter->name());
+  timer->Start(counter, stats->current_timer());
   stats->current_timer_.SetValue(timer);
   stats->current_counter_.SetValue(counter);
 }
@@ -487,17 +490,11 @@ void RuntimeCallStats::Enter(RuntimeCallStats* stats, RuntimeCallTimer* timer,
 // static
 void RuntimeCallStats::Leave(RuntimeCallStats* stats, RuntimeCallTimer* timer) {
   DCHECK(stats->IsCalledOnTheSameThread());
-  if (stats->current_timer_.Value() != timer) {
-    // The branch is added to catch a crash crbug.com/760649
-    RuntimeCallTimer* stack_top = stats->current_timer_.Value();
-    EmbeddedVector<char, 200> text;
-    SNPrintF(text, "ERROR: Leaving counter '%s', stack top '%s'.\n",
-             timer->name(), stack_top ? stack_top->name() : "(null)");
-    USE(text);
-    CHECK(false);
-  }
+  RuntimeCallTimer* stack_top = stats->current_timer();
+  if (stack_top == nullptr) return;  // Missing timer is a result of Reset().
+  CHECK(stack_top == timer);
   stats->current_timer_.SetValue(timer->Stop());
-  RuntimeCallTimer* cur_timer = stats->current_timer_.Value();
+  RuntimeCallTimer* cur_timer = stats->current_timer();
   stats->current_counter_.SetValue(cur_timer ? cur_timer->counter() : nullptr);
 }
 
@@ -513,8 +510,10 @@ void RuntimeCallStats::Add(RuntimeCallStats* other) {
 // static
 void RuntimeCallStats::CorrectCurrentCounterId(RuntimeCallStats* stats,
                                                CounterId counter_id) {
+  DCHECK(stats->IsCalledOnTheSameThread());
+  // When RCS are enabled dynamically there might be no stats or timer set up.
+  if (stats == nullptr) return;
   RuntimeCallTimer* timer = stats->current_timer_.Value();
-  // When RCS are enabled dynamically there might be no current timer set up.
   if (timer == nullptr) return;
   RuntimeCallCounter* counter = &(stats->*counter_id);
   timer->set_counter(counter);
@@ -528,6 +527,11 @@ bool RuntimeCallStats::IsCalledOnTheSameThread() {
   return true;
 }
 
+void RuntimeCallStats::Print() {
+  OFStream os(stdout);
+  Print(os);
+}
+
 void RuntimeCallStats::Print(std::ostream& os) {
   RuntimeCallStatEntries entries;
   if (current_timer_.Value() != nullptr) {