[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 05c60c722c317cca7bf6e52453a5faba1d7b1903..2463f1a7366b86be9f5d21cd3fb2465ca1fd1cad 100644
--- a/base/trace_event/heap_profiler_allocation_context_tracker_unittest.cc
+++ b/base/trace_event/heap_profiler_allocation_context_tracker_unittest.cc
@@ -10,6 +10,7 @@
 #include "base/pending_task.h"
 #include "base/trace_event/heap_profiler_allocation_context.h"
 #include "base/trace_event/heap_profiler_allocation_context_tracker.h"
+#include "base/trace_event/heap_profiler_scoped_ignore.h"
 #include "base/trace_event/trace_event.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -278,5 +279,17 @@ 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 ctx1 =
+      AllocationContextTracker::GetInstanceForCurrentThread()
+          ->GetContextSnapshot();
+  const StringPiece kTracingOverhead("tracing_overhead");
+  ASSERT_EQ(kTracingOverhead, ctx1.backtrace.frames[0]);
+  ASSERT_FALSE(ctx1.backtrace.frames[1]);

[Primiano Tucci (use gerrit), 2016/04/21 19:47:32]

this is not guaranteed to be nullptr anymore.
This should check that frame_count == 1

[ssid, 2016/04/22 04:57:12]

Done.

+}
+
 }  // namespace trace_event
 }  // namespace base