Refactor StringPiece hash.

Rename struct BASE_HASH_NAMESPACE::hash<base::StringPiece> to struct
base::StringPieceHash, and modify existing code as necessary.  This is motivated
by https://crrev.com/1660273002/#msg6.

* Remove #include "base/containers/hash_tables.h" where not used any more.
* Add this include for hash_map where necessary (string_piece.h does not include
  it any longer, so this might be necessary for the code to compile).
* Change net::linked_hash_map from base::hash_map to std::unordered_map and add
  Hash template parameter.  This way BASE_HASH_NAMESPACE::hash<Key> will not be
  implicitly used any more, so move QuicBlockedWriterInterfacePtrHash out of
  that namespace.

BUG=576864

Review URL: https://codereview.chromium.org/1666843002

Cr-Commit-Position: refs/heads/master@{#374005}

1 files changed, 3 insertions, 3 deletions

diff --git a/net/base/linked_hash_map.h b/net/base/linked_hash_map.h
index b86654b..e3d12d6 100644
--- a/net/base/linked_hash_map.h
+++ b/net/base/linked_hash_map.h
@@ -18,9 +18,9 @@
 #include <stddef.h>
 
 #include <list>
+#include <unordered_map>
 #include <utility>
 
-#include "base/containers/hash_tables.h"
 #include "base/logging.h"
 #include "base/macros.h"
 
@@ -30,11 +30,11 @@
 //
 // We also keep a map<Key, list::iterator> for find.  Since std::list is a
 // doubly-linked list, the iterators should remain stable.
-template<class Key, class Value>
+template <class Key, class Value, class Hash = std::hash<Key>>
 class linked_hash_map {
  private:
   typedef std::list<std::pair<Key, Value> > ListType;
-  typedef base::hash_map<Key, typename ListType::iterator> MapType;
+  typedef std::unordered_map<Key, typename ListType::iterator, Hash> MapType;
 
  public:
   typedef typename ListType::iterator iterator;