[tracing] Fix V8 and PartitionAlloc dump provider for background mode

gin/v8_isolate_memory_dump_provider.cc

 // 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.
 
 #include "gin/v8_isolate_memory_dump_provider.h"
 
 #include <stddef.h>
 
 #include "base/strings/stringprintf.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ skipping 113 matching lines @@
                          base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                          heap_statistics.malloced_memory());
   const char* system_allocator_name =
       base::trace_event::MemoryDumpManager::GetInstance()
           ->system_allocator_pool_name();
   if (system_allocator_name) {
     process_memory_dump->AddSuballocation(malloc_dump->guid(),
                                           system_allocator_name);
   }
 
-  // If light dump is requested, then object statistics are not dumped
-  if (args.level_of_detail == base::trace_event::MemoryDumpLevelOfDetail::LIGHT)
+  // Only if heavy dump is requested, then object statistics are dumped.

[Primiano Tucci (use gerrit), 2016/06/01 09:58:26]

The wording of this comment is a bit odd now.
Maybe:
// Dump object statistics only for detailed dumps.

[ssid, 2016/06/01 18:53:46]

Done.

+  if (args.level_of_detail !=
+      base::trace_event::MemoryDumpLevelOfDetail::DETAILED) {
     return;
+  }
 
   // Dump statistics of the heap's live objects from last GC.
   // TODO(primiano): these should not be tracked in the same trace event as they
   // report stats for the last GC (not the current state). See crbug.com/498779.
   std::string object_name_prefix = dump_base_name + "/heap_objects_at_last_gc";
   bool did_dump_object_stats = false;
   const size_t object_types =
       isolate_holder_->isolate()->NumberOfTrackedHeapObjectTypes();
   for (size_t type_index = 0; type_index < object_types; type_index++) {
     v8::HeapObjectStatistics object_statistics;
@@ skipping 28 matching lines @@
   }
 
   if (did_dump_object_stats) {
     process_memory_dump->AddOwnershipEdge(
         process_memory_dump->CreateAllocatorDump(object_name_prefix)->guid(),
         process_memory_dump->CreateAllocatorDump(space_name_prefix)->guid());
   }
 }
 
 }  // namespace gin