Add UMA stats to record when DLLs are successfully blocked in the Browser.

chrome_elf/dll_hash/dll_hash.cc

Index: chrome_elf/dll_hash/dll_hash.cc
diff --git a/chrome_elf/dll_hash/dll_hash.cc b/chrome_elf/dll_hash/dll_hash.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f9c1dd81d25dd6d9cb790b1a32fbeeaa94161703
--- /dev/null
+++ b/chrome_elf/dll_hash/dll_hash.cc
@@ -0,0 +1,14 @@
+// Copyright (c) 2014 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.
+
+#include "base/hash.h"
+#include "chrome_elf/dll_hash/dll_hash.h"
+
+int DllNameToHash(std::string dll_name) {
+  uint32 data = base::Hash(dll_name);
+
+  // Strip off the signed bit because UMA doesn't support negative values,
+  // but takes a signed int as input.
+  return static_cast<int>(data & 0x7fffffff);
+}