Heap Profiler: Add trace category group names as type names for allocations

base/trace_event/heap_profiler_allocation_context_tracker.h

Index: base/trace_event/heap_profiler_allocation_context_tracker.h
diff --git a/base/trace_event/heap_profiler_allocation_context_tracker.h b/base/trace_event/heap_profiler_allocation_context_tracker.h
index 454200c474ee32be54c15e234cfa1753a8e580ce..c080c095b497c19fba240e65c61eb6c16bc7aa21 100644
--- a/base/trace_event/heap_profiler_allocation_context_tracker.h
+++ b/base/trace_event/heap_profiler_allocation_context_tracker.h
@@ -69,10 +69,10 @@ class BASE_EXPORT AllocationContextTracker {
   }
 
   // Pushes a frame onto the thread-local pseudo stack.
-  void PushPseudoStackFrame(const char* trace_event_name);
+  void PushPseudoStackFrame(const char* category, const char* trace_event_name);
 
   // Pops a frame from the thread-local pseudo stack.
-  void PopPseudoStackFrame(const char* trace_event_name);
+  void PopPseudoStackFrame(const char* category, const char* trace_event_name);
 
   // Push and pop current task's context. A stack is used to support nested
   // tasks and the top of the stack will be used in allocation context.
@@ -99,6 +99,10 @@ class BASE_EXPORT AllocationContextTracker {
   // pseudo stack to cluster allocations.
   std::vector<const char*> task_contexts_;
 
+  // If task context was unavailable, then the category names from trace_events
+  // are used to cluster allcoations.
+  std::vector<const char*> trace_categories_;
+
   uint32_t ignore_scope_depth_;
 
   DISALLOW_COPY_AND_ASSIGN(AllocationContextTracker);