Mojo C++ bindings: change the first template parameter of StructTraits and UnionTraits.

mojo/public/cpp/bindings/union_traits.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_UNION_TRAITS_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_UNION_TRAITS_H_
 
 namespace mojo {
 
 // This must be specialized for any type |T| to be serialized/deserialized as
-// a mojom union of type |MojomType|.
+// a mojom union. |DataViewType| is the corresponding data view type of the
+// mojom union. For example, if the mojom union is example.Foo, |DataViewType|
+// will be example::FooDataView, which can also be referred to by
+// example::Foo::DataView (in chromium) and example::blink::Foo::DataView (in
+// blink).
 //
 // Similar to StructTraits, each specialization of UnionTraits implements the
 // following methods:
 //   1. Getters for each field in the Mojom type.
 //   2. Read() method.
 //   3. [Optional] IsNull() and SetToNull().
 //   4. [Optional] SetUpContext() and TearDownContext().
 // Please see the documentation of StructTraits for details of these methods.
 //
 // Unlike StructTraits, there is one more method to implement:
 //   5. A static GetTag() method indicating which field is the current active
 //      field for serialization:
 //
-//        static |MojomType|DataView::Tag GetTag(const T& input);
+//        static DataViewType::Tag GetTag(const T& input);
 //
 //      During serialization, only the field getter corresponding to this tag
 //      will be called.
 //
-template <typename MojomType, typename T>
+template <typename DataViewType, typename T>
 struct UnionTraits;
 
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_UNION_TRAITS_H_