Add a histogram for renderer memory usage.

webkit/glue/memory_usage.h

Index: webkit/glue/memory_usage.h
diff --git a/webkit/glue/memory_usage.h b/webkit/glue/memory_usage.h
new file mode 100644
index 0000000000000000000000000000000000000000..e0b5bc9ba342c0f90013d4c4736e3e59198ea77b
--- /dev/null
+++ b/webkit/glue/memory_usage.h
@@ -0,0 +1,18 @@
+// Copyright (c) 2013 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 WEBKIT_GLUE_MEMORY_USAGE_H_
+#define WEBKIT_GLUE_MEMORY_USAGE_H_
+
+#include <cstring>
+
+#include "webkit/glue/webkit_glue_export.h"
+
+namespace webkit_glue {
+
+WEBKIT_GLUE_EXPORT size_t memoryUsageKB();

[Charlie Reis, 2013/01/14 19:59:31]

Presumably you're accounting for the fact that it's a different measurement on
each platform.  Maybe it's worth documenting here what this value is
specifically returning for each platform?

[marja, 2013/01/14 20:17:01]

Yes, we're not comparing these values across platforms. Added here:
// Returns an estimate of the memory usage of the renderer process. Different
// platforms implement this function differently, and count in different
// allocations. Results are not comparable across platforms. The estimate is
// computed inside the sandbox and thus its not always accurate.

+
+}  // namespace webkit_glue
+
+#endif  // WEBKIT_GLUE_MEMORY_USAGE_H_