Revert of [tracing] Turn StackFrame into struct.

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 e5c8c187739b99afaa0f75995b1a534dd14a2e4d..d6133323bfb3d8f88f4331f6c718582c5611b3ee 100644
--- a/base/trace_event/heap_profiler_allocation_context_tracker.h
+++ b/base/trace_event/heap_profiler_allocation_context_tracker.h
@@ -53,10 +53,10 @@
   static void SetCurrentThreadName(const char* name);
 
   // Pushes a frame onto the thread-local pseudo stack.
-  void PushPseudoStackFrame(const char* trace_event_name);
+  void PushPseudoStackFrame(StackFrame frame);
 
   // Pops a frame from the thread-local pseudo stack.
-  void PopPseudoStackFrame(const char* trace_event_name);
+  void PopPseudoStackFrame(StackFrame frame);
 
   // 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.
@@ -74,7 +74,7 @@
   static subtle::Atomic32 capture_enabled_;
 
   // The pseudo stack where frames are |TRACE_EVENT| names.
-  std::vector<const char*> pseudo_stack_;
+  std::vector<StackFrame> pseudo_stack_;
 
   // The thread name is used as the first entry in the pseudo stack.
   const char* thread_name_;