Add a copy of the SMHasher library. MurmurHash3 will be used by SafeBrowsing phishing detection.

third_party/smhasher/smhasher.gyp

Index: third_party/smhasher/smhasher.gyp
diff --git a/third_party/smhasher/smhasher.gyp b/third_party/smhasher/smhasher.gyp
new file mode 100644
index 0000000000000000000000000000000000000000..fa59c2c1c8ac2197eb0e64fb9e297424476dd984
--- /dev/null
+++ b/third_party/smhasher/smhasher.gyp
@@ -0,0 +1,16 @@
+# 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.
+
+{
+  'targets': [
+    {
+      'target_name': 'murmurhash3',
+      'type': 'static_library',
+      'sources': [
+        'src/MurmurHash3.h',
+        'src/MurmurHash3.cpp',
+      ],
+    },
+  ],
+}