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

base/memory/shared_memory_tracker.cc

 // Copyright 2017 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 "base/memory/shared_memory_tracker.h"
 
-#include "base/memory/shared_memory.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/process_memory_dump.h"
 
 namespace base {
 
+namespace {
+
+std::string SharedMemoryUniqueIdToString(const SharedMemory::UniqueId& id) {
+#if defined(OS_POSIX) && (!defined(OS_MACOSX) || defined(OS_IOS))
+  return StringPrintf("%s/%lld.%lld", "shared_memory",
+                      static_cast<long long>(id.first),
+                      static_cast<long long>(id.second));
+#else
+  // TODO(hajimehoshi): Implement this.
+  return "";
+#endif
+}
+}
+
 SharedMemoryTracker::Usage::Usage() = default;
 
 SharedMemoryTracker::Usage::Usage(const Usage& rhs) = default;
 
 SharedMemoryTracker::Usage::~Usage() = default;
 
 // static
 SharedMemoryTracker* SharedMemoryTracker::GetInstance() {
   static SharedMemoryTracker* instance = new SharedMemoryTracker;
   return instance;
 }
 
+// static
+bool SharedMemoryTracker::AddOwnershipEdges(
+    trace_event::ProcessMemoryDump* pmd,
+    const trace_event::MemoryAllocatorDumpGuid& source,
+    const SharedMemoryHandle& shared_memory_handle,
+    size_t mapped_size) {
+  SharedMemory::UniqueId id;
+  if (!SharedMemory::GetUniqueId(shared_memory_handle, &id))
+    return false;
+
+  // TODO: Fix the dump name
+  std::string id_str = SharedMemoryUniqueIdToString(id);
+  auto in_process_dump_name =
+      StringPrintf("shared_memory_in_process/%s", id_str.c_str());
+  auto* in_process_dump = pmd->CreateAllocatorDump(in_process_dump_name);
+  pmd->AddOwnershipEdge(source, in_process_dump->guid());
+  in_process_dump->AddScalar(trace_event::MemoryAllocatorDump::kNameSize,
+                             trace_event::MemoryAllocatorDump::kUnitsBytes,
+                             mapped_size);
+
+  trace_event::MemoryAllocatorDumpGuid global_guid(id_str);
+  pmd->AddOwnershipEdge(in_process_dump->guid(), global_guid);
+  return true;
+}
+
 void SharedMemoryTracker::IncrementMemoryUsage(
     const SharedMemory& shared_memory) {
   Usage usage;
   // |shared_memory|'s unique ID must be generated here and it'd be too late at
   // OnMemoryDump. An ID is generated with a SharedMemoryHandle, but the handle
   // might already be closed at that time. Now IncrementMemoryUsage is called
   // just after mmap and the handle must live then. See the discussion at
   // crbug.com/604726#c30.
   SharedMemory::UniqueId id;
-  if (!shared_memory.GetUniqueId(&id))
+  if (!SharedMemory::GetUniqueId(shared_memory.handle(), &id))
     return;
   usage.unique_id = id;
   usage.size = shared_memory.mapped_size();
   AutoLock hold(usages_lock_);
   usages_[&shared_memory] = usage;
 }
 
 void SharedMemoryTracker::DecrementMemoryUsage(
     const SharedMemory& shared_memory) {
   AutoLock hold(usages_lock_);
   usages_.erase(&shared_memory);
 }
 
 bool SharedMemoryTracker::OnMemoryDump(const trace_event::MemoryDumpArgs& args,
                                        trace_event::ProcessMemoryDump* pmd) {
   std::unordered_map<SharedMemory::UniqueId, size_t, SharedMemory::UniqueIdHash>
       sizes;
   {
     AutoLock hold(usages_lock_);
     for (const auto& usage : usages_)
       sizes[usage.second.unique_id] += usage.second.size;
   }
   for (auto& size : sizes) {
     const SharedMemory::UniqueId& id = size.first;
-    std::string dump_name = StringPrintf("%s/%lld.%lld", "shared_memory",
-                                         static_cast<long long>(id.first),
-                                         static_cast<long long>(id.second));
+    std::string dump_name = SharedMemoryUniqueIdToString(id);
     auto guid = trace_event::MemoryAllocatorDumpGuid(dump_name);
     trace_event::MemoryAllocatorDump* local_dump =
         pmd->CreateAllocatorDump(dump_name);
     // TODO(hajimehoshi): The size is not resident size but virtual size so far.
     // Fix this to record resident size.
     local_dump->AddScalar(trace_event::MemoryAllocatorDump::kNameSize,
                           trace_event::MemoryAllocatorDump::kUnitsBytes,
                           size.second);
     trace_event::MemoryAllocatorDump* global_dump =
         pmd->CreateSharedGlobalAllocatorDump(guid);
@@ skipping 10 matching lines @@
 }
 
 SharedMemoryTracker::SharedMemoryTracker() {
   trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
       this, "SharedMemoryTracker", nullptr);
 }
 
 SharedMemoryTracker::~SharedMemoryTracker() = default;
 
 }  // namespace