[WIP] Add SharedMemoryTracker to dump base::SharedMemory usage

components/discardable_memory/common/discardable_shared_memory_heap.cc

 // Copyright 2014 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 "components/discardable_memory/common/discardable_shared_memory_heap.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/format_macros.h"
 #include "base/macros.h"
 #include "base/memory/discardable_shared_memory.h"
 #include "base/memory/ptr_util.h"
+#include "base/memory/shared_memory_tracker.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/memory_dump_manager.h"
 
 namespace discardable_memory {
 namespace {
 
 bool IsPowerOfTwo(size_t x) {
   return (x & (x - 1)) == 0;
 }
 
@@ skipping 385 matching lines @@
   obj_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameObjectCount,
                       base::trace_event::MemoryAllocatorDump::kUnitsObjects,
                       allocated_objects_count);
   obj_dump->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
                       base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                       allocated_objects_size_in_bytes);
   obj_dump->AddScalar("locked_size",
                       base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                       locked_objects_size_in_bytes);
 
-  // Emit an ownership edge towards a global allocator dump node. This allows
-  // to avoid double-counting segments when both browser and client process emit
-  // them. In the special case of single-process-mode, this will be the only
-  // dumper active and the single ownership edge will become a no-op in the UI.
-  // The global dump is created as a weak dump so that the segment is removed if
-  // the browser does not dump it (segment was purged).
-  const uint64_t tracing_process_id =
-      base::trace_event::MemoryDumpManager::GetInstance()
-          ->GetTracingProcessId();
-  base::trace_event::MemoryAllocatorDumpGuid shared_segment_guid =
-      GetSegmentGUIDForTracing(tracing_process_id, segment_id);
-  // TODO(ssid): Make this weak once the GUID created is consistent
-  // crbug.com/661257.
-  pmd->CreateSharedGlobalAllocatorDump(shared_segment_guid);
-
-  // The size is added to the global dump so that it gets propagated to both the
-  // dumps associated.
-  pmd->GetSharedGlobalAllocatorDump(shared_segment_guid)
-      ->AddScalar(base::trace_event::MemoryAllocatorDump::kNameSize,
-                  base::trace_event::MemoryAllocatorDump::kUnitsBytes,
-                  allocated_objects_size_in_bytes);
-
-  // By creating an edge with a higher |importance| (w.r.t. browser-side dumps)
-  // the tracing UI will account the effective size of the segment to the
-  // client.
-  const int kImportance = 2;
-  pmd->AddOwnershipEdge(segment_dump->guid(), shared_segment_guid, kImportance);
+  base::SharedMemoryTracker::AddOwnershipEdges(pmd, obj_dump->guid(),
+                                               shared_memory->shared_memory());
 }
 
 // static
 base::trace_event::MemoryAllocatorDumpGuid
 DiscardableSharedMemoryHeap::GetSegmentGUIDForTracing(
     uint64_t tracing_process_id,
     int32_t segment_id) {
   return base::trace_event::MemoryAllocatorDumpGuid(base::StringPrintf(
       "discardable-x-process/%" PRIx64 "/%d", tracing_process_id, segment_id));
 }
@@ skipping 14 matching lines @@
   auto it =
       std::find_if(memory_segments_.begin(), memory_segments_.end(),
                    [span](const std::unique_ptr<ScopedMemorySegment>& segment) {
                      return segment->ContainsSpan(span);
                    });
   DCHECK(it != memory_segments_.end());
   return (*it)->CreateMemoryAllocatorDump(span, block_size_, name, pmd);
 }
 
 }  // namespace discardable_memory