Add incremental updates for multipage distillation.

components/dom_distiller/core/article_distillation_update.cc

+// Copyright 2014 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.
+
+#include "components/dom_distiller/core/article_distillation_update.h"
+
+#include "base/logging.h"
+
+namespace dom_distiller {
+
+ArticleDistillationUpdate::ArticleDistillationUpdate(
+    const std::vector<RefPtrToDistilledPageProto>& pages,
+    bool has_next_page,
+    bool has_prev_page)
+    : has_next_page_(has_next_page),
+      has_prev_page_(has_prev_page),
+      pages_(pages) {}
+
+ArticleDistillationUpdate::~ArticleDistillationUpdate() {}
+
+const ArticleDistillationUpdate::RefPtrToDistilledPageProto
+ArticleDistillationUpdate::GetDistilledPage(size_t index) const {
+  DCHECK_GT(pages_.size(), index);
+  return pages_[index];
+}
+
+}  // namespace dom_distiller