Add ownership edges between HostSharedBitmap and shared memory

base/trace_event/process_memory_dump.h

Index: base/trace_event/process_memory_dump.h
diff --git a/base/trace_event/process_memory_dump.h b/base/trace_event/process_memory_dump.h
index 6f8d167273327e2488ae30f12ca53928c810543d..a8e7c66ef3dd1481dc7da8073cdd25d43d4f39e7 100644
--- a/base/trace_event/process_memory_dump.h
+++ b/base/trace_event/process_memory_dump.h
@@ -53,6 +53,8 @@ class BASE_EXPORT ProcessMemoryDump {
   using HeapDumpsMap =
       std::unordered_map<std::string, std::unique_ptr<TracedValue>>;
 
+  static const int kDefaultImportance = 0;
+
 #if defined(COUNT_RESIDENT_BYTES_SUPPORTED)
   // Returns the number of bytes in a kernel memory page. Some platforms may
   // have a different value for kernel page sizes from user page sizes. It is