[tracing] Ignore tracing allocations in heap profiler

base/trace_event/heap_profiler_allocation_context_tracker.cc

Index: base/trace_event/heap_profiler_allocation_context_tracker.cc
diff --git a/base/trace_event/heap_profiler_allocation_context_tracker.cc b/base/trace_event/heap_profiler_allocation_context_tracker.cc
index 1fc8bc008a522419f7b1eb454c9b45a6d8c739b0..399c48c765643fa39a22731d6ad46974f9d8a48c 100644
--- a/base/trace_event/heap_profiler_allocation_context_tracker.cc
+++ b/base/trace_event/heap_profiler_allocation_context_tracker.cc
@@ -22,6 +22,7 @@ const size_t kMaxStackDepth = 128u;
 const size_t kMaxTaskDepth = 16u;
 AllocationContextTracker* const kInitializingSentinel =
     reinterpret_cast<AllocationContextTracker*>(-1);
+const char kTracingOverhead[] = "tracing_overhead";
 
 ThreadLocalStorage::StaticSlot g_tls_alloc_ctx_tracker = TLS_INITIALIZER;
 
@@ -50,7 +51,8 @@ AllocationContextTracker::GetInstanceForCurrentThread() {
   return tracker;
 }
 
-AllocationContextTracker::AllocationContextTracker() : thread_name_(nullptr) {
+AllocationContextTracker::AllocationContextTracker()
+    : thread_name_(nullptr), ignore_scope_count_(0) {
   pseudo_stack_.reserve(kMaxStackDepth);
   task_contexts_.reserve(kMaxTaskDepth);
 }
@@ -119,6 +121,13 @@ void AllocationContextTracker::PopCurrentTaskContext(const char* context) {
 AllocationContext AllocationContextTracker::GetContextSnapshot() {
   AllocationContext ctx;
 
+  if (ignore_scope_count_) {
+    ctx = AllocationContext::Empty();

[Primiano Tucci (use gerrit), 2016/04/20 16:34:57]

I think either you or dskiba need to rebase on top of each other :)

[ssid, 2016/04/21 01:07:46]

Yes was waiting for it to land. Done.

+    ctx.backtrace.frames[0] = kTracingOverhead;
+    ctx.type_name = kTracingOverhead;
+    return ctx;
+  }
+
   // Fill the backtrace.
   {
     auto src = pseudo_stack_.begin();