Avoid string construction overhead for lookup-only HpackEntry objects.

net/spdy/hpack/hpack_header_table_test.cc

Index: net/spdy/hpack/hpack_header_table_test.cc
diff --git a/net/spdy/hpack/hpack_header_table_test.cc b/net/spdy/hpack/hpack_header_table_test.cc
index dc730103292a3042ff0e20f9d567c7bc29b9e075..86b688b3aad47d734086efb7605e97b1d6eefb81 100644
--- a/net/spdy/hpack/hpack_header_table_test.cc
+++ b/net/spdy/hpack/hpack_header_table_test.cc
@@ -79,7 +79,7 @@ class HpackHeaderTableTest : public ::testing::Test {
     EXPECT_GE(size, HpackEntry::kSizeOverhead);
     string name((size - HpackEntry::kSizeOverhead) / 2, 'n');
     string value(size - HpackEntry::kSizeOverhead - name.size(), 'v');
-    HpackEntry entry(name, value);
+    HpackEntry entry(name, value, false, 0);
     EXPECT_EQ(size, entry.Size());
     return entry;
   }