Revert of Revert "Update legacy Tuple-using code."

base/tuple.h

Index: base/tuple.h
diff --git a/base/tuple.h b/base/tuple.h
index a0d22454abde023b5fe298d52ac78127c6cd2d2b..4408074335b3bd2c28b5ee5719a0b63ba262971c 100644
--- a/base/tuple.h
+++ b/base/tuple.h
@@ -123,71 +123,6 @@
 
   T x;
 };
-
-// For legacy compatibility, we name the first 8 tuple elements "a", "b", ...
-// TODO(mdempsky): Update users to use get<N>() (crbug.com/440675).
-
-#define DEFINE_TUPLE_LEAF(N, x)                                        \
-  template <typename T>                                                \
-  struct TupleLeaf<N, T> {                                             \
-    TupleLeaf() {}                                                     \
-    explicit TupleLeaf(typename TupleTraits<T>::ParamType x) : x(x) {} \
-                                                                       \
-    T& get() { return x; }                                             \
-    const T& get() const { return x; }                                 \
-                                                                       \
-    T x;                                                               \
-  }
-
-DEFINE_TUPLE_LEAF(0, a);
-DEFINE_TUPLE_LEAF(1, b);
-DEFINE_TUPLE_LEAF(2, c);
-DEFINE_TUPLE_LEAF(3, d);
-DEFINE_TUPLE_LEAF(4, e);
-DEFINE_TUPLE_LEAF(5, f);
-DEFINE_TUPLE_LEAF(6, g);
-DEFINE_TUPLE_LEAF(7, h);
-
-#undef DEFINE_TUPLE_LEAF
-
-// Deprecated compat aliases
-// TODO(mdempsky): Update users to just use Tuple instead (crbug.com/440675).
-
-using Tuple0 = Tuple<>;
-template <typename A>
-using Tuple1 = Tuple<A>;
-template <typename A, typename B>
-using Tuple2 = Tuple<A, B>;
-template <typename A, typename B, typename C>
-using Tuple3 = Tuple<A, B, C>;
-template <typename A, typename B, typename C, typename D>
-using Tuple4 = Tuple<A, B, C, D>;
-template <typename A, typename B, typename C, typename D, typename E>
-using Tuple5 = Tuple<A, B, C, D, E>;
-template <typename A,
-          typename B,
-          typename C,
-          typename D,
-          typename E,
-          typename F>
-using Tuple6 = Tuple<A, B, C, D, E, F>;
-template <typename A,
-          typename B,
-          typename C,
-          typename D,
-          typename E,
-          typename F,
-          typename G>
-using Tuple7 = Tuple<A, B, C, D, E, F, G>;
-template <typename A,
-          typename B,
-          typename C,
-          typename D,
-          typename E,
-          typename F,
-          typename G,
-          typename H>
-using Tuple8 = Tuple<A, B, C, D, E, F, G, H>;
 
 // Tuple getters --------------------------------------------------------------
 //