[tracing] Adding task information to heap profiler

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 34e6f38a5bf0056a8cc297808eb5eef2abbd199c..0cf0e4d2de7349149ccdc99142e7970a65f343f0 100644
--- a/base/trace_event/heap_profiler_allocation_context_tracker.h
+++ b/base/trace_event/heap_profiler_allocation_context_tracker.h
@@ -23,6 +23,17 @@ namespace trace_event {
 // details.
 class BASE_EXPORT AllocationContextTracker {
  public:
+  class ScopedTaskExecutionEvent {
+   public:
+    ScopedTaskExecutionEvent(const char* category_group,
+                             const char* posted_reason);

[Primiano Tucci (use gerrit), 2016/03/25 01:56:31]

I think these should be called poster_task_file_name and
poster_task_function_name
Also, looks like you never use the 2nd argument, so let's remove it

[ssid, 2016/03/28 18:14:49]

calling it context, can change if you prefer to be more specific. I think if we
decide to use something else in context instead of file name, it need not be
changed.

+
+    ~ScopedTaskExecutionEvent();
+
+   private:
+    const char* category_;
+  };
+
   // Globally enables capturing allocation context.
   // TODO(ruuda): Should this be replaced by |EnableCapturing| in the future?
   // Or at least have something that guards agains enable -> disable -> enable?
@@ -67,9 +78,16 @@ class BASE_EXPORT AllocationContextTracker {
 
   static subtle::Atomic32 capture_enabled_;
 
+  void PushCurrentCategoryName(const char* category);

[Primiano Tucci (use gerrit), 2016/03/25 01:56:31]

I'm a bit confused by the "Category" name here.
Can we call these just PushPosterTaskName

[ssid, 2016/03/28 18:14:49]

Hm it is not exactly task name. To be specific I should call it
TaskPostedFromFilename. Gets too specific and we can't use it in future if we
wanted to add some other context here. So, i am renaming it to TaskContext, to
keep it generic but still makes enough sense.

+  void PopCurrentCategoryName(const char* category);
+
   // The pseudo stack where frames are |TRACE_EVENT| names.
   std::vector<StackFrame> pseudo_stack_;
 
+  // Category can be nested when tasks are nested. So, a stack is used and the
+  // last item is taken for the current allocation.
+  std::vector<const char*> categories_;
+
   DISALLOW_COPY_AND_ASSIGN(AllocationContextTracker);
 };