Limit the time spent on a single iteration of PhishingDOMFeatureExtractor.

chrome/renderer/safe_browsing/feature_extractor_clock.h

+// Copyright (c) 2010 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.
+//
+// A simple abstraction for getting the current time during feature extraction.
+// This can be mocked out for testing.
+
+#ifndef CHROME_RENDERER_SAFE_BROWSING_FEATURE_EXTRACTOR_CLOCK_H_
+#define CHROME_RENDERER_SAFE_BROWSING_FEATURE_EXTRACTOR_CLOCK_H_
+
+#include "base/time.h"
+
+namespace safe_browsing {
+
+class FeatureExtractorClock {
+ public:
+  FeatureExtractorClock() {}
+  virtual ~FeatureExtractorClock() {}
+
+  // Returns the current time.  May be mocked for testing.
+  virtual base::TimeTicks Now() { return base::TimeTicks::Now(); }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(FeatureExtractorClock);
+};
+
+}  // namespace safe_browsing
+
+#endif  // CHROME_RENDERER_SAFE_BROWSING_FEATURE_EXTRACTOR_CLOCK_H_