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
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+// 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/gtest_prod_util.h"
+#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 laid out
+// according to the specification at https://goto.google.com/ais_api.
+//
+// Each of the three classes has either an explicit or implicity copy
+// constructor to support copying answer values (via SuggestionAnswer::copy) as
+// members of SuggestResult and AutocompleteMatch.
+class SuggestionAnswer {
+ public:
+  class TextField;
+  typedef std::vector<TextField> TextFields;
+  typedef std::vector<GURL> URLs;
+
+  class TextField {
+   public:
+    TextField();
+    ~TextField();
+
+    // Parses |field_json| and populates |text_field| with the contents.  If any
+    // of the required elements is missing, returns false and leaves text_field
+    // in a partially populated state.
+    static bool ParseTextField(const base::DictionaryValue* field_json,
+                               TextField* text_field);
+
+    const std::string& text() const { return text_; }
+    int type() const { return type_; }
+
+    bool Equals(const TextField& field) const;
+
+   private:
+    std::string text_;
+    int type_;
+
+    FRIEND_TEST_ALL_PREFIXES(SuggestionAnswerTest, DifferentValuesAreUnequal);
+
+    // No DISALLOW_COPY_AND_ASSIGN since we depend on the copy constructor in
+    // SuggestionAnswer::copy and the assigment operator as values in vector.
+  };
+
+  class ImageLine {
+   public:
+    ImageLine();
+    explicit ImageLine(const ImageLine& line);
+    ~ImageLine();
+
+    // Parses |line_json| and populates |image_line| with the contents.  If any
+    // of the required elements is missing, returns false and leaves text_field
+    // in a partially populated state.
+    static bool ParseImageLine(const base::DictionaryValue* line_json,
+                               ImageLine* image_line);
+
+    const TextFields& text_fields() const { return text_fields_; }
+    const TextField* additional_text() const { return additional_text_.get(); }
+    const TextField* status_text() const { return status_text_.get(); }
+    const GURL& image_url() const { return image_url_; }
+
+    bool Equals(const ImageLine& line) const;
+
+   private:
+    // Forbid assignment.
+    ImageLine& operator=(const ImageLine&);
+
+    TextFields text_fields_;
+    scoped_ptr<TextField> additional_text_;
+    scoped_ptr<TextField> status_text_;
+    GURL image_url_;
+
+    FRIEND_TEST_ALL_PREFIXES(SuggestionAnswerTest, DifferentValuesAreUnequal);
+  };
+
+  SuggestionAnswer();
+  SuggestionAnswer(const SuggestionAnswer& answer);
+  ~SuggestionAnswer();
+
+  // Parses |answer_json| and returns a SuggestionAnswer containing the
+  // contents.  If the supplied data is not well formed or is missing required
+  // elements, returns nullptr instead.
+  static scoped_ptr<SuggestionAnswer> ParseAnswer(
+        const base::DictionaryValue* answer_json);
+
+  // TODO(jdonnelly): Once something like std::optional<T> is available in base/
+  // (see discussion at http://goo.gl/zN2GNy) remove this in favor of having
+  // SuggestResult and AutocompleteMatch use optional<SuggestionAnswer>.
+  static scoped_ptr<SuggestionAnswer> copy(const SuggestionAnswer* source) {
+    return make_scoped_ptr(source ? new SuggestionAnswer(*source) : nullptr);
+  }
+
+  const ImageLine& first_line() const { return first_line_; }
+  const ImageLine& second_line() const { return second_line_; }
+
+  // Answer type accessors.  Valid types are non-negative and defined at
+  // https://goto.google.com/visual_element_configuration.
+  int type() const { return type_; }
+  void set_type(int type) { type_ = type; }
+
+  bool Equals(const SuggestionAnswer& answer) const;
+
+  // Retrieves any image URLs appearing in this answer and adds them to |urls|.
+  void AddImageURLsTo(URLs* urls) const;
+
+ private:
+  // Forbid assignment.
+  SuggestionAnswer& operator=(const SuggestionAnswer&);
+
+  ImageLine first_line_;
+  ImageLine second_line_;
+  int type_;
+
+  FRIEND_TEST_ALL_PREFIXES(SuggestionAnswerTest, DifferentValuesAreUnequal);
+};
+
+#endif  // COMPONENTS_OMNIBOX_SUGGESTION_ANSWER_H_