[tracing] Simplify MemoryDumpProvider interface

base/trace_event/memory_dump_provider.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_MEMORY_DUMP_PROVIDER_H_
 #define BASE_TRACE_EVENT_MEMORY_DUMP_PROVIDER_H_
 
 #include "base/base_export.h"
-#include "base/memory/ref_counted.h"
-#include "base/trace_event/memory_allocator_attributes_type_info.h"
 
 namespace base {
-
-class SingleThreadTaskRunner;
-
 namespace trace_event {
 
 class ProcessMemoryDump;
 
 // The contract interface that memory dump providers must implement.
 class BASE_EXPORT MemoryDumpProvider {
  public:
   // Called by the MemoryDumpManager when generating memory dumps.
-  // Returns: true if the |pmd| was successfully populated, false otherwise.
-  virtual bool DumpInto(ProcessMemoryDump* pmd) = 0;
-
-  virtual const char* GetFriendlyName() const = 0;
-
-  const MemoryAllocatorAttributesTypeInfo& allocator_attributes_type_info()
-      const {
-    return allocator_attributes_type_info_;
-  }
-
-  // The dump provider can specify an optional thread affinity (in its
-  // base constructor call). If |task_runner| is non empty, all the calls to
-  // DumpInto are guaranteed to be posted to that TaskRunner.
-  const scoped_refptr<SingleThreadTaskRunner>& task_runner() const {
-    return task_runner_;
-  }
-
- protected:
-  // Default ctor: the MDP is not bound to any thread (must be a singleton).
-  MemoryDumpProvider();
-
-  // Use this ctor to ensure that DumpInto() is called always on the same thread
-  // specified by |task_runner|.
-  explicit MemoryDumpProvider(
-      const scoped_refptr<SingleThreadTaskRunner>& task_runner);
-
-  virtual ~MemoryDumpProvider();

[reveman, 2015/04/27 23:01:24]

Can we keep an empty protected dtor to prevent this from being destroyed
incorrectly?

[Primiano Tucci (use gerrit), 2015/04/28 08:03:03]

Done.

-
-  void DeclareAllocatorAttribute(const std::string& allocator_name,
-                                 const std::string& attribute_name,
-                                 const std::string& attribute_type);
-
- private:
-  // A map of attributes types (declared through DeclareAllocatorAttribute())
-  // emitted by this allocator dumper.
-  MemoryAllocatorAttributesTypeInfo allocator_attributes_type_info_;
-
-  // (Optional) TaskRunner on which the DumpInfo call should be posted.
-  scoped_refptr<SingleThreadTaskRunner> task_runner_;
-
-  DISALLOW_COPY_AND_ASSIGN(MemoryDumpProvider);
+  // The embedder should return true if the |pmd| was successfully populated,
+  // false if something went wrong and the dump should be considered invalid.
+  // (Note, the MemoryDumpManager has a fail-safe logic which will disable the
+  // MemoryDumpProvider for the entire trace session if it fails consistently).
+  virtual bool OnMemoryDump(ProcessMemoryDump* pmd) = 0;
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_MEMORY_DUMP_PROVIDER_H_