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

components/discardable_memory/service/discardable_shared_memory_manager.cc

Index: components/discardable_memory/service/discardable_shared_memory_manager.cc
diff --git a/components/discardable_memory/service/discardable_shared_memory_manager.cc b/components/discardable_memory/service/discardable_shared_memory_manager.cc
index e2966c798c78bfafbc28f69e0d85095aa9f89582..64d719adcfbefa7a630eb9195c6542f0c7f815ab 100644
--- a/components/discardable_memory/service/discardable_shared_memory_manager.cc
+++ b/components/discardable_memory/service/discardable_shared_memory_manager.cc
@@ -16,6 +16,7 @@
 #include "base/memory/discardable_memory.h"
 #include "base/memory/memory_coordinator_client_registry.h"
 #include "base/memory/ptr_util.h"
+#include "base/memory/shared_memory_tracker.h"
 #include "base/numerics/safe_math.h"
 #include "base/process/memory.h"
 #include "base/strings/string_number_conversions.h"
@@ -40,24 +41,8 @@
 namespace discardable_memory {
 namespace {
 
-const char kSingleProcess[] = "single-process";
-
 const int kInvalidUniqueClientID = -1;
 
-const uint64_t kBrowserTracingProcessId = std::numeric_limits<uint64_t>::max();
-
-uint64_t ClientProcessUniqueIdToTracingProcessId(int client_id) {
-  // TODO(penghuang): Move this function to right place.
-  // https://crbug.com/661257
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(kSingleProcess))
-    return kBrowserTracingProcessId;
-  // The hash value is incremented so that the tracing id is never equal to
-  // MemoryDumpManager::kInvalidTracingProcessId.
-  return static_cast<uint64_t>(base::Hash(
-             reinterpret_cast<const char*>(&client_id), sizeof(client_id))) +
-         1;
-}
-
 // mojom::DiscardableSharedMemoryManager implementation. It contains the
 // |client_id_| which is not visible to client. We associate allocations with a
 // given mojo instance, so if the instance is closed, we can release the
@@ -321,27 +306,25 @@ bool DiscardableSharedMemoryManager::OnMemoryDump(
       // corresponding dump for the same segment, this will avoid to
       // double-count them in tracing. If, instead, no other process will emit a
       // dump with the same guid, the segment will be accounted to the browser.
-      const uint64_t client_tracing_id =
-          ClientProcessUniqueIdToTracingProcessId(client_id);
-      base::trace_event::MemoryAllocatorDumpGuid shared_segment_guid =
-          DiscardableSharedMemoryHeap::GetSegmentGUIDForTracing(
-              client_tracing_id, segment_id);
-      pmd->CreateSharedGlobalAllocatorDump(shared_segment_guid);
-      pmd->AddOwnershipEdge(dump->guid(), shared_segment_guid);
+
+      base::SharedMemoryTracker::AddOwnershipEdges(
+          pmd, dump->guid(), segment->memory()->handle(),
+          segment->memory()->mapped_size());
 
 #if defined(COUNT_RESIDENT_BYTES_SUPPORTED)
       if (args.level_of_detail ==
           base::trace_event::MemoryDumpLevelOfDetail::DETAILED) {
-        size_t resident_size =
+        // TODO: Fix this
+        /*size_t resident_size =
             base::trace_event::ProcessMemoryDump::CountResidentBytes(
-                segment->memory()->memory(), segment->memory()->mapped_size());
+            segment->memory()->memory(), segment->memory()->mapped_size());*/
 
         // This is added to the global dump since it has to be attributed to
         // both the allocator dumps involved.
-        pmd->GetSharedGlobalAllocatorDump(shared_segment_guid)
+        /*pmd->GetSharedGlobalAllocatorDump(shared_segment_guid)
             ->AddScalar("resident_size",

[hajimehoshi, 2017/03/27 10:05:01]

I have no idea what is the difference between 'resident_size' here and 'size'
and how to treat this with my fix.

                         base::trace_event::MemoryAllocatorDump::kUnitsBytes,
-                        static_cast<uint64_t>(resident_size));
+                        static_cast<uint64_t>(resident_size));*/
       }
 #endif  // defined(COUNT_RESIDENT_BYTES_SUPPORTED)
     }