Implement basic classes for HPACK (HTTP/2 compression)

net/spdy/hpack_string_util.cc

Index: net/spdy/hpack_string_util.cc
diff --git a/net/spdy/hpack_string_util.cc b/net/spdy/hpack_string_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5c0b131a2e11cfa8de8bf1ecf7baa4ce59672ba6
--- /dev/null
+++ b/net/spdy/hpack_string_util.cc
@@ -0,0 +1,20 @@
+#include "net/spdy/hpack_string_util.h"
+
+#include "base/basictypes.h"
+
+namespace net {
+
+bool StringPiecesEqualConstantTime(base::StringPiece str1,
+                                   base::StringPiece str2) {
+  size_t size = str1.size();
+  if (str2.size() != size)
+    return false;
+
+  uint8 x = 0;
+  for (size_t i = 0; i < size; ++i) {
+    x |= str1[i] ^ str2[i];
+  }
+  return x == 0;
+}
+
+}  // namespace net