[tracing] Introduce MemoryDumpArgs to enable light and heavy dumps

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/macros.h"
 
 namespace base {
 namespace trace_event {
 
 class ProcessMemoryDump;
 
+struct MemoryDumpArgs {

[petrcermak, 2015/07/31 13:23:01]

Could you please explain the relationship between MemoryDumpArgs (added in this
patch) and MemoryDumpRequestArgs (existing class:
https://code.google.com/p/chromium/codesearch#chromium/src/base/trace_event/m...
)? I'm wondering whether they should be the same thing.

[ssid, 2015/07/31 15:14:33]

Hm, the MemoryDumpRequestArgs is used to request a global dump, contains what
type of dump is to be taken to the manager. This args is to tell the dump
provider what kind of dump to take. I can't merge both since the providers need
not know what triggered the dump or the global dump guid.

The PERIODIC_INTERVAL_WITH_MMAPS will be removed and maybe MemoryDumpArgs should
be a part of MemoryDumpRequest args for requesting.

[petrcermak, 2015/08/03 10:12:35]

OK, this makes sense. Thanks for the explanation.

+  enum LevelOfDetail { LEVEL_OF_DETAIL_LOW, LEVEL_OF_DETAIL_HIGH };
+
+  explicit MemoryDumpArgs(const LevelOfDetail level) : level_of_detail(level) {}
+
+  LevelOfDetail level_of_detail;

[petrcermak, 2015/07/31 13:23:01]

const?

[ssid, 2015/07/31 15:14:33]

Done.

+};
+
 // The contract interface that memory dump providers must implement.
 class BASE_EXPORT MemoryDumpProvider {
  public:
   // Called by the MemoryDumpManager when generating memory dumps.
   // 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;
+  virtual bool OnMemoryDump(const MemoryDumpArgs& args,
+                            ProcessMemoryDump* pmd) = 0;
 
  protected:
   MemoryDumpProvider() {}
   virtual ~MemoryDumpProvider() {}
 
   DISALLOW_COPY_AND_ASSIGN(MemoryDumpProvider);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_MEMORY_DUMP_PROVIDER_H_