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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef CHROME_BROWSER_UI_WEBUI_NTP_SUGGESTIONS_SOURCE_H_
      6 #define CHROME_BROWSER_UI_WEBUI_NTP_SUGGESTIONS_SOURCE_H_
      7 
      8 #include "base/basictypes.h"
      9 
     10 class Profile;
     11 class SuggestionsCombiner;
     12 
     13 namespace base {
     14 class DictionaryValue;
     15 }
     16 
     17 // Interface for a source of suggested pages. The various sources will be
     18 // combined by the SuggestionsCombiner.
     19 class SuggestionsSource {
     20 
     21  public:
     22   virtual ~SuggestionsSource() {}
     23 
     24  protected:
     25   SuggestionsSource() {}
     26 
     27   friend class SuggestionsCombiner;
     28 
     29   // Enables or disables debug mode for the current source. The source is
     30   // expected to provide additional data when debug mode is enabled.
     31   virtual void SetDebug(bool enable) = 0;
     32 
     33   // The source's weight indicates how many items from this source will be
     34   // selected by the combiner. If a source weight is x and the total weight of
     35   // all the sources is y, then the combiner will select x/y items from it.
     36   virtual int GetWeight() = 0;
     37 
     38   // Returns the number of items this source can produce.
     39   virtual int GetItemCount() = 0;
     40 
     41   // Removes the most important item from this source and returns it. The
     42   // returned item must be in the right format to be sent to the javascript,
     43   // which you typically get by calling NewTabUI::SetUrlTitleAndDirection. If
     44   // the source is empty this method returns null.
     45   // The caller takes ownership of the returned item.
     46   virtual base::DictionaryValue* PopItem() = 0;
     47 
     48   // Requests that the source fetch its items. If the source is already fetching
     49   // it does not have to reset and can continue fetching.
     50   virtual void FetchItems(Profile* profile) = 0;
     51 
     52   // Sets the combiner holding this suggestion source. This method can only
     53   // be called once.
     54   virtual void SetCombiner(SuggestionsCombiner* combiner) = 0;
     55 
     56  private:
     57   DISALLOW_COPY_AND_ASSIGN(SuggestionsSource);
     58 };
     59 
     60 #endif  // CHROME_BROWSER_UI_WEBUI_NTP_SUGGESTIONS_SOURCE_H_
     61