Add ownership edges between HostSharedBitmap and shared memory

content/common/host_shared_bitmap_manager.cc

Index: content/common/host_shared_bitmap_manager.cc
diff --git a/content/common/host_shared_bitmap_manager.cc b/content/common/host_shared_bitmap_manager.cc
index f424ac3623e84ead3652816225c6e58b38fef67c..72109efe1d1f8aa8c412c74ca7a569e6410d6a61 100644
--- a/content/common/host_shared_bitmap_manager.cc
+++ b/content/common/host_shared_bitmap_manager.cc
@@ -12,6 +12,7 @@
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/shared_memory_tracker.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/trace_event/process_memory_dump.h"
 #include "build/build_config.h"
@@ -41,7 +42,7 @@ class HostSharedBitmap : public cc::SharedBitmap {
                    scoped_refptr<BitmapData> bitmap_data,
                    const cc::SharedBitmapId& id,
                    HostSharedBitmapManager* manager)
-      : SharedBitmap(pixels, id),
+      : SharedBitmap(pixels, nullptr, id),
         bitmap_data_(bitmap_data),
         manager_(manager) {}
 
@@ -173,11 +174,9 @@ bool HostSharedBitmapManager::OnMemoryDump(
                     base::trace_event::MemoryAllocatorDump::kUnitsBytes,
                     bitmap.second->buffer_size);
 
-    // Generate a global GUID used to share this allocation with renderer
-    // processes.
-    auto guid = cc::GetSharedBitmapGUIDForTracing(bitmap.first);
-    pmd->CreateSharedGlobalAllocatorDump(guid);

[hajimehoshi, 2017/03/28 11:44:35]

There are still CreateSharedGlobalAllocatorDump calls. I'm not sure it is
allowed to mix CreateSharedGlobalAllocatorDump usages and my new
SharedMemoryTracker::AddOwnershipEdges.

-    pmd->AddOwnershipEdge(dump->guid(), guid);
+    base::SharedMemoryTracker::AddOwnershipEdges(
+        pmd, dump->guid(), bitmap.second->memory->handle(),
+        bitmap.second->buffer_size);
   }
 
   return true;
@@ -225,7 +224,7 @@ void HostSharedBitmapManager::AllocateSharedBitmapForChild(
     *shared_memory_handle = base::SharedMemory::NULLHandle();
     return;
   }
- data->memory->Close();
+  data->memory->Close();
 }
 
 void HostSharedBitmapManager::ChildDeletedSharedBitmap(