Factor cpu profile tree into separate element and expose allocation tracing UI

runtime/vm/profiler.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_PROFILER_H_
 #define VM_PROFILER_H_
 
 #include "vm/allocation.h"
 #include "vm/bitfield.h"
 #include "vm/code_observers.h"
@@ skipping 454 matching lines @@
   void set_vm_tag(uword tag) { vm_tag_ = tag; }
 
   // The user tag.
   uword user_tag() const { return user_tag_; }
   void set_user_tag(uword tag) { user_tag_ = tag; }
 
   // The class id if this is an allocation profile sample. -1 otherwise.
   intptr_t allocation_cid() const { return allocation_cid_; }
   void set_allocation_cid(intptr_t cid) { allocation_cid_ = cid; }
 
+  bool IsAllocationSample() const {
+    return allocation_cid_ > 0;
+  }
+
   // Was the stack trace truncated?
   bool truncated() const { return truncated_; }
   void set_truncated(bool truncated) { truncated_ = truncated; }
 
   // Was the first frame in the stack trace executing?
   bool first_frame_executing() const { return first_frame_executing_; }
   void set_first_frame_executing(bool first_frame_executing) {
     first_frame_executing_ = first_frame_executing;
   }
 
@@ skipping 49 matching lines @@
 
  private:
   ZoneGrowableArray<ProcessedSample*> samples_;
 
   DISALLOW_COPY_AND_ASSIGN(ProcessedSampleBuffer);
 };
 
 }  // namespace dart
 
 #endif  // VM_PROFILER_H_