[tracing] Introduce "allowed_dump_modes" for memory dump config

base/trace_event/memory_dump_request_args.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_REQUEST_ARGS_H_
 #define BASE_TRACE_EVENT_MEMORY_DUMP_REQUEST_ARGS_H_
 
 // This file defines the types and structs used to issue memory dump requests.
 // These are also used in the IPCs for coordinating inter-process memory dumps.
 
@@ skipping 10 matching lines @@
 // selective enabling of dumps, filtering and post-processing.
 enum class MemoryDumpType {
   TASK_BEGIN,         // Dumping memory at the beginning of a message-loop task.
   TASK_END,           // Dumping memory at the ending of a message-loop task.
   PERIODIC_INTERVAL,  // Dumping memory at periodic intervals.
   EXPLICITLY_TRIGGERED,  // Non maskable dump request.
   LAST = EXPLICITLY_TRIGGERED // For IPC macros.
 };
 
 // Tells the MemoryDumpProvider(s) how much detailed their dumps should be.
-enum class MemoryDumpLevelOfDetail {
+enum class MemoryDumpLevelOfDetail : uint32_t {

[oystein (OOO til 10th of July), 2016/06/20 17:02:18]

Why do you need to explicitly specify the storage type?

[ssid, 2016/06/20 19:12:06]

Because I am casting this later, so thought it is safer to specify the type here
as well.

   // For background tracing mode. The dump time is quick, and typically just the
   // totals are expected. Suballocations need not be specified. Dump name must
   // contain only pre-defined strings and string arguments cannot be added.
   BACKGROUND,
 
   // For the levels below, MemoryDumpProvider instances must guarantee that the
   // total size reported in the root node is consistent. Only the granularity of
   // the child MemoryAllocatorDump(s) differs with the levels.
 
   // Few entries, typically a fixed number, per dump.
   LIGHT,
 
   // Unrestricted amount of entries per dump.
   DETAILED,
 
-  // For IPC Macros.
+  FIRST = BACKGROUND,

[oystein (OOO til 10th of July), 2016/06/20 17:02:18]

Nit: "FIRST" should probably be first in the list, to make it more obvious that
it should get updated if someone prepends something.

[ssid, 2016/06/20 19:12:06]

Done.

   LAST = DETAILED
 };
 
 // Initial request arguments for a global memory dump. (see
 // MemoryDumpManager::RequestGlobalMemoryDump()).
 struct BASE_EXPORT MemoryDumpRequestArgs {
   // Globally unique identifier. In multi-process dumps, all processes issue a
   // local dump with the same guid. This allows the trace importers to
   // reconstruct the global dump.
   uint64_t dump_guid;
@@ skipping 16 matching lines @@
 BASE_EXPORT const char* MemoryDumpLevelOfDetailToString(
     const MemoryDumpLevelOfDetail& level_of_detail);
 
 BASE_EXPORT MemoryDumpLevelOfDetail
 StringToMemoryDumpLevelOfDetail(const std::string& str);
 
 }  // namespace trace_event
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_MEMORY_DUMP_REQUEST_ARGS_H_