Add partitionsOutOfMemoryUsingXXX to know Blink memory usage from OOM crash reports

Source/wtf/Alias.h

Index: Source/wtf/Alias.h
diff --git a/Source/wtf/Alias.h b/Source/wtf/Alias.h
new file mode 100644
index 0000000000000000000000000000000000000000..9d0ff7522cade73ae4c903d80b012367035ab516
--- /dev/null
+++ b/Source/wtf/Alias.h
@@ -0,0 +1,19 @@
+// Copyright (c) 2011 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.
+
+#ifndef Alias_h
+#define Alias_h
+
+#include "wtf/WTFExport.h"
+
+namespace WTF {
+
+// Make the optimizer think that var is aliased. This is to prevent it from
+// optimizing out variables that would not otherwise be live at the point
+// of a potential crash.
+void WTF_EXPORT alias(const void* var);
+
+} // namespace WTF
+
+#endif // Alias_h