Add a term feature extractor for client-side phishing detection.

chrome/renderer/safe_browsing/features.h

Index: chrome/renderer/safe_browsing/features.h
diff --git a/chrome/renderer/safe_browsing/features.h b/chrome/renderer/safe_browsing/features.h
index f3c8348cc4c3c548dd4d65f260647780ba30f2f5..82370c154fb548829aeed2929420c128b4690888 100644
--- a/chrome/renderer/safe_browsing/features.h
+++ b/chrome/renderer/safe_browsing/features.h
@@ -158,6 +158,16 @@ extern const char kPageNumScriptTagsGTSix[];
 // The fraction of images whose src attribute points to an external domain.
 extern const char kPageImgOtherDomainFreq[];
 
+////////////////////////////////////////////////////
+// Page term features
+////////////////////////////////////////////////////
+
+// Token feature for a term (whitespace-delimited) on a page.  Terms can be
+// single words or multi-word n-grams.  Rather than adding this feature for
+// every possible token on a page, only the terms that are mentioned in the
+// classification model are added.
+extern const char kPageTerm[];
+
 }  // namespace features
 }  // namepsace safe_browsing