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

base/sha2.cc

Index: base/sha2.cc
diff --git a/base/sha2.cc b/base/sha2.cc
index b6d6d5659c258684198d4ac1995d7d1f265dd9c4..47d381b18cf94bb3dd463455d1c6c413f1ad0152 100644
--- a/base/sha2.cc
+++ b/base/sha2.cc
@@ -4,6 +4,7 @@
 
 #include "base/sha2.h"
 
+#include "base/stl_util-inl.h"
 #include "base/third_party/nss/blapi.h"
 #include "base/third_party/nss/sha256.h"
 
@@ -19,4 +20,10 @@ void SHA256HashString(const std::string& str, void* output, size_t len) {
              static_cast<unsigned int>(len));
 }
 
+std::string SHA256HashString(const std::string& str) {
+  std::string output(SHA256_LENGTH, 0);
+  SHA256HashString(str, string_as_array(&output), str.size());
+  return output;
+}
+
 }  // namespace base