[tracing] Add filtering mode in TraceLog

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 cbece2b14ff85eafb009b22229e220a8b1f991e2..767f3616cd46caacc1d8991793f22049b14d3511 100644
--- a/base/trace_event/heap_profiler_allocation_context_tracker.cc
+++ b/base/trace_event/heap_profiler_allocation_context_tracker.cc
@@ -129,7 +129,9 @@ void AllocationContextTracker::PopPseudoStackFrame(
   // hit if some TRACE_EVENT macro is unbalanced (a TRACE_EVENT_END* call
   // without a corresponding TRACE_EVENT_BEGIN).
   DCHECK(stack_frame == pseudo_stack_.back())
-      << "Encountered an unmatched TRACE_EVENT_END";
+      << "Encountered an unmatched TRACE_EVENT_END: "
+      << stack_frame.trace_event_name
+      << ", event in stack: " << pseudo_stack_.back().trace_event_name;

[Primiano Tucci (use gerrit), 2016/09/23 18:34:31]

I'd probably s/,/vs/

[ssid, 2016/09/26 18:39:53]

Done.

 
   pseudo_stack_.pop_back();
 }