Add incremental updates for multipage distillation.

components/dom_distiller/core/article_distillation_update.h

+// 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.
+
+#ifndef COMPONENTS_DOM_DISTILLER_CORE_ARTICLE_DISTILLATION_UPDATE_H_
+#define COMPONENTS_DOM_DISTILLER_CORE_ARTICLE_DISTILLATION_UPDATE_H_
+
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "components/dom_distiller/core/proto/distilled_page.pb.h"
+
+namespace dom_distiller {
+
+// Update about an article that is currently under distillation.
+class ArticleDistillationUpdate {
+ public:
+  typedef scoped_refptr<base::RefCountedData<DistilledPageProto> >
+      RefPtrToDistilledPageProto;

[cjhopman, 2014/03/04 02:29:05]

How would you feel about just doing:

typedef base::RefCountedData<DistilledPageProto> RefCountedPageProto;

or RefCountedDistilledPage;

[shashi, 2014/03/04 19:47:23]

Done.

+
+  ArticleDistillationUpdate(
+      const std::vector<RefPtrToDistilledPageProto>& pages,
+      bool has_next_page,
+      bool has_prev_page);
+  ~ArticleDistillationUpdate();
+
+  const RefPtrToDistilledPageProto GetDistilledPage(size_t index) const;
+
+  size_t GetPagesSize() const { return pages_.size(); }

[nyquist, 2014/03/03 23:00:12]

I've mostly seen calls to size() of a local variable to also have hacker case,
so I'd say get_pages_size(), but both exist in our codebase.

[cjhopman, 2014/03/04 02:29:05]

Yeah, I was tempted to suggest that but it seemed to violate the style guide. I
would be happy with either one as long as these three are all the same. I think
I suggested this case because it matches GetDistilledPage() above.

+
+  bool HasNextPage() const { return has_next_page_; }

[nyquist, 2014/03/03 23:00:12]

I think this should be has_next_page, and similarly below.

[cjhopman, 2014/03/04 02:29:05]

According to the style guide, this is optional.

+
+  bool HasPrevPage() const { return has_prev_page_; }
+
+ private:
+  // True, if article has a next page.

[nyquist, 2014/03/03 23:00:12]

Whether article has a next page. Same below.
Also, could you specify that this means that the article has pages that are not
part of the current set of pages? As it stands right now, it is a little bit
confusing as to what these two booleans really represent.

[shashi, 2014/03/04 19:47:23]

Clarified and moved the comments to the public interface of the class.
On 2014/03/03 23:00:12, nyquist wrote:

+  bool has_next_page_;
+  // True, if article has a previous page.
+  bool has_prev_page_;
+  // Currently available pages.
+  std::vector<RefPtrToDistilledPageProto> pages_;
+};
+
+}  // namespace dom_distiller
+
+#endif  // COMPONENTS_DOM_DISTILLER_CORE_ARTICLE_DISTILLATION_UPDATE_H_