[tracing] Add native allocation tracing mode.

base/trace_event/heap_profiler_allocation_context.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_TRACE_EVENT_HEAP_PROFILER_ALLOCATION_CONTEXT_H_
 #define BASE_TRACE_EVENT_HEAP_PROFILER_ALLOCATION_CONTEXT_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 26 matching lines @@
 
 // Represents (pseudo) stack frame. Used in Backtrace class below.
 //
 // Conceptually stack frame is identified by its value, and type is used
 // mostly to properly format the value. Value is expected to be a valid
 // pointer from process' address space.
 struct BASE_EXPORT StackFrame {
   enum class Type {
     TRACE_EVENT_NAME,   // const char* string
     THREAD_NAME,        // const char* thread name
+    PROGRAM_COUNTER,    // as returned by stack tracing (e.g. by StackTrace)
   };
 
   static StackFrame FromTraceEventName(const char* name) {
     return {Type::TRACE_EVENT_NAME, name};
   }
   static StackFrame FromThreadName(const char* name) {
     return {Type::THREAD_NAME, name};
   }
+  static StackFrame FromProgramCounter(const void* pc) {
+    return {Type::PROGRAM_COUNTER, pc};
+  }
 
   Type type;
   const void* value;
 };
 
 bool BASE_EXPORT operator < (const StackFrame& lhs, const StackFrame& rhs);
 bool BASE_EXPORT operator == (const StackFrame& lhs, const StackFrame& rhs);
 bool BASE_EXPORT operator != (const StackFrame& lhs, const StackFrame& rhs);
 
 struct BASE_EXPORT Backtrace {
@@ skipping 59 matching lines @@
 };
 
 template <>
 struct BASE_EXPORT hash<base::trace_event::AllocationContext> {
   size_t operator()(const base::trace_event::AllocationContext& context) const;
 };
 
 }  // BASE_HASH_NAMESPACE
 
 #endif  // BASE_TRACE_EVENT_HEAP_PROFILER_ALLOCATION_CONTEXT_H_