Update from https://crrev.com/327068

base/test/mock_entropy_provider.cc

Index: base/test/mock_entropy_provider.cc
diff --git a/base/test/mock_entropy_provider.cc b/base/test/mock_entropy_provider.cc
new file mode 100644
index 0000000000000000000000000000000000000000..75186a56a1adb5102f5828f7e1c725a4940400e8
--- /dev/null
+++ b/base/test/mock_entropy_provider.cc
@@ -0,0 +1,16 @@
+// Copyright 2015 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/test/mock_entropy_provider.h"
+
+namespace base {
+
+MockEntropyProvider::~MockEntropyProvider() {}
+
+double MockEntropyProvider::GetEntropyForTrial(
+    const std::string& trial_name, uint32 randomization_seed) const {
+  return 0.5;
+}
+
+}  // namespace base