Add ownership edges between HostSharedBitmap and shared memory

base/memory/shared_memory.h

Index: base/memory/shared_memory.h
diff --git a/base/memory/shared_memory.h b/base/memory/shared_memory.h
index 4b66cc6edd2c61ab12d28a00e3b0d8a53daad877..952deec5f60f7aa0fdac26a99e2f2467efd831b6 100644
--- a/base/memory/shared_memory.h
+++ b/base/memory/shared_memory.h
@@ -265,9 +265,22 @@ class BASE_EXPORT SharedMemory {
     }
   };
 
-  // Returns a unique ID for this shared memory's handle. Note this function may
+  // Returns a unique ID for the shared memory |handle|. Note this function may
   // access file system and be slow.
-  bool GetUniqueId(UniqueId* id) const;
+  static bool GetUniqueId(const SharedMemoryHandle& handle, UniqueId* id);
+#else
+  // TODO(hajimehoshi): On platforms other than POSIX, UniqueId and its getter
+  // are work in progress.
+  using UniqueId = int;
+
+  struct UniqueIdHash {
+    size_t operator()(const UniqueId& id) const { return id; }
+  };
+
+  static bool GetUniqueId(const SharedMemoryHandle& handle, UniqueId* id) {
+    *id = 0;
+    return true;
+  }
 #endif
 
  private: