Add a class to parse answer json.

components/omnibox/suggestion_answer.h

Index: components/omnibox/suggestion_answer.h
diff --git a/components/omnibox/suggestion_answer.h b/components/omnibox/suggestion_answer.h
new file mode 100644
index 0000000000000000000000000000000000000000..db73dbe0163d659f2973428ee960d0fdf788ef8b
--- /dev/null
+++ b/components/omnibox/suggestion_answer.h
@@ -0,0 +1,107 @@
+// 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_OMNIBOX_SUGGESTION_ANSWER_H_
+#define COMPONENTS_OMNIBOX_SUGGESTION_ANSWER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/memory/scoped_ptr.h"
+#include "url/gurl.h"
+
+namespace base {
+class DictionaryValue;
+}
+
+// Structured representation of the JSON payload of a suggestion with an answer.
+// An answer has exactly two image lines, so called because they are a
+// combination of text and an optional image URL.  Each image line has 1 or more
+// text fields, each of which is required to contain a string and an integer
+// type.  The text fields are contained in a non-empty vector and two optional
+// named properties, referred to as "additional text" and "status text".
+//
+// When represented in the UI, these elements should be styled and layed out
+// according to the specification at http://goto.google.com/ais_api.
+class SuggestionAnswer {
+ public:
+  class TextField {
+   public:
+    TextField();
+    ~TextField();
+
+    static bool ParseTextField(

[groby-ooo-7-16, 2014/10/21 00:35:54]

Why not have a simple struct, plus a factory? Saves you from writing accessors,
comparison, etc.

[Justin Donnelly, 2014/10/21 21:43:54]

I like the consistency of design across these three classes.  Plus, while this
is currently very simple, I think it might get more complex (see next comment).

+        const base::DictionaryValue* field_json, TextField* text_field);
+
+    bool operator==(const TextField& field) const;
+    bool operator!=(const TextField& field) const;
+
+    const std::string& text() const { return text_; }
+    int type() const { return type_; }
+
+    void Clear();
+
+   private:
+    std::string text_;
+    int type_;
+  };
+
+  typedef std::vector<TextField> TextFields;

[groby-ooo-7-16, 2014/10/21 00:35:54]

I wonder if TextFields should be a single string + a vector of <type, index,
len> 3-tuples instead. At least copy cost is somewhat reduced, if we go the
"copy it all" route.

[Justin Donnelly, 2014/10/21 21:43:54]

My concern with this is that we discussed a similar structure for each TextField
after parsing HTML tags in the strings.  If we also do this, we'll end up with a
complex structure to represent the indexes of the various segments.

+
+  class ImageLine {
+   public:
+    ImageLine();
+    ~ImageLine();
+
+    static bool ParseImageLine(
+        const base::DictionaryValue* line_json, ImageLine* image_line);
+
+    bool operator==(const ImageLine& line) const;
+    bool operator!=(const ImageLine& line) const;
+
+    const std::vector<TextField>& text_fields() const { return text_fields_; }
+    const TextField& additional_text() const { return additional_text_; }
+    const TextField& status_text() const { return status_text_; }
+
+    bool HasImageURL() const;
+    const GURL& image_url() const { return image_url_; }
+
+    void Clear();
+
+   private:
+    TextFields text_fields_;
+    TextField additional_text_;
+    TextField status_text_;
+    GURL image_url_;
+  };
+
+  SuggestionAnswer();
+  ~SuggestionAnswer();
+
+  static bool ParseAnswer(
+        const std::string& answer_json, SuggestionAnswer* answer);
+  static bool ParseAnswer(
+        const base::DictionaryValue* answer_json, SuggestionAnswer* answer);
+
+  bool operator==(const SuggestionAnswer& answer) const;
+  bool operator!=(const SuggestionAnswer& answer) const;
+
+  const ImageLine& first_line() const { return first_line_; }
+  const ImageLine& second_line() const { return second_line_; }
+  int type() const { return type_; }
+  bool is_valid() const { return is_valid_; }
+
+  // Specify the type of this answer. The string will be interpreted as a base10
+  // integer. If it can't be parsed as such, the type will be set to 0.
+  void SetType(const base::string16& type);
+  void Clear();
+
+ private:
+  ImageLine first_line_;
+  ImageLine second_line_;
+  int type_;
+  bool is_valid_;
+};
+
+#endif  // COMPONENTS_OMNIBOX_SUGGESTION_ANSWER_H_