[tracing] Introduce MemoryDumpArgs to enable light and heavy dumps

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 "base/strings/stringprintf.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/process_memory_dump.h"
@@ skipping 10 matching lines @@
 }
 
 V8IsolateMemoryDumpProvider::~V8IsolateMemoryDumpProvider() {
   base::trace_event::MemoryDumpManager::GetInstance()->UnregisterDumpProvider(
       this);
 }
 
 // Called at trace dump point time. Creates a snapshot with the memory counters
 // for the current isolate.
 bool V8IsolateMemoryDumpProvider::OnMemoryDump(
+    const base::trace_event::MemoryDumpArgs& args,
     base::trace_event::ProcessMemoryDump* process_memory_dump) {
+  // TODO(ssid): Use MemoryDumpArgs to create light dumps when requested
+  // (crbug.com/499731).
+
   if (isolate_holder_->access_mode() == IsolateHolder::kUseLocker) {
     v8::Locker locked(isolate_holder_->isolate());
     DumpHeapStatistics(process_memory_dump);
   } else {
     DumpHeapStatistics(process_memory_dump);
   }
   return true;
 }
 
 void V8IsolateMemoryDumpProvider::DumpHeapStatistics(
@@ skipping 85 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