[tracing] Ignore tracing allocations in heap profiler

base/trace_event/heap_profiler_allocation_context_tracker_unittest.cc

Index: base/trace_event/heap_profiler_allocation_context_tracker_unittest.cc
diff --git a/base/trace_event/heap_profiler_allocation_context_tracker_unittest.cc b/base/trace_event/heap_profiler_allocation_context_tracker_unittest.cc
index a39700e4fff4171d6701883d83d6a8ef98a85cdd..ed037049001ef7463c6211c931a0795c74457d79 100644
--- a/base/trace_event/heap_profiler_allocation_context_tracker_unittest.cc
+++ b/base/trace_event/heap_profiler_allocation_context_tracker_unittest.cc
@@ -8,6 +8,7 @@
 
 #include "base/memory/ref_counted.h"
 #include "base/pending_task.h"
+#include "base/trace_event/heap_profiler.h"
 #include "base/trace_event/heap_profiler_allocation_context.h"
 #include "base/trace_event/heap_profiler_allocation_context_tracker.h"
 #include "base/trace_event/trace_event.h"
@@ -278,5 +279,18 @@ TEST_F(AllocationContextTrackerTest, TrackTaskContext) {
   ASSERT_FALSE(ctx.type_name);
 }
 
+TEST_F(AllocationContextTrackerTest, IgnoreAllocationTest) {
+  TRACE_EVENT0("Testing", kCupcake);
+  TRACE_EVENT0("Testing", kDonut);
+  HEAP_PROFILER_SCOPED_IGNORE;
+  AllocationContext ctx =
+      AllocationContextTracker::GetInstanceForCurrentThread()
+          ->GetContextSnapshot();
+  const StringPiece kTracingOverhead("tracing_overhead");
+  ASSERT_EQ(kTracingOverhead,
+            static_cast<const char*>(ctx.backtrace.frames[0].value));
+  ASSERT_EQ(1u, ctx.backtrace.frame_count);
+}
+
 }  // namespace trace_event
 }  // namespace base