Add support for distilling arbitrary URLs in DOM Distiller Viewer.

components/dom_distiller/core/dom_distiller_service.h

Index: components/dom_distiller/core/dom_distiller_service.h
diff --git a/components/dom_distiller/core/dom_distiller_service.h b/components/dom_distiller/core/dom_distiller_service.h
index 630b184e5eb5e2fda8e5054fbfb5b649c4ad335b..8f4ea70f7bed5f4a69d685deb205e92a9977e02e 100644
--- a/components/dom_distiller/core/dom_distiller_service.h
+++ b/components/dom_distiller/core/dom_distiller_service.h
@@ -30,42 +30,73 @@ class TaskTracker;
 class ViewerHandle;
 class ViewRequestDelegate;
 
-// Provide a view of the article list and ways of interacting with it.
-class DomDistillerService {
+// Service for interacting with the Dom Distiller.
+// Construction, destruction, and usage of this service must happen on the same
+// thread. Callbacks will be called on that same thread.
+class DomDistillerServiceInterface {
  public:
   typedef base::Callback<void(bool)> ArticleAvailableCallback;
+  virtual ~DomDistillerServiceInterface() {}
 
-  DomDistillerService(scoped_ptr<DomDistillerStoreInterface> store,
-                      scoped_ptr<DistillerFactory> distiller_factory);
-  ~DomDistillerService();
-
-  syncer::SyncableService* GetSyncableService() const;
+  virtual syncer::SyncableService* GetSyncableService() const = 0;
 
   // Distill the article at |url| and add the resulting entry to the DOM
-  // distiller list. |article_cb| is invoked with true if article is
-  // available offline.
-  const std::string AddToList(const GURL& url,
-                              const ArticleAvailableCallback& article_cb);
+  // distiller list. |article_cb| is always invoked, and the bool argument to it
+  // represents whether the article is available offline.
+  virtual const std::string AddToList(
+      const GURL& url,
+      const ArticleAvailableCallback& article_cb) = 0;
 
   // Gets the full list of entries.
-  std::vector<ArticleEntry> GetEntries() const;
+  virtual std::vector<ArticleEntry> GetEntries() const = 0;
 
   // Removes the specified entry from the dom distiller store.
-  scoped_ptr<ArticleEntry> RemoveEntry(const std::string& entry_id);
+  virtual scoped_ptr<ArticleEntry> RemoveEntry(const std::string& entry_id) = 0;
 
   // Request to view an article by entry id. Returns a null pointer if no entry
   // with |entry_id| exists. The ViewerHandle should be destroyed before the
   // ViewRequestDelegate. The request will be cancelled when the handle is
-  // destroyed (or when this service is destroyed).
-  scoped_ptr<ViewerHandle> ViewEntry(ViewRequestDelegate* delegate,
-                                     const std::string& entry_id);
+  // destroyed (or when this service is destroyed), which also ensures that
+  // the |delegate| is not called after that.
+  virtual scoped_ptr<ViewerHandle> ViewEntry(ViewRequestDelegate* delegate,
+                                             const std::string& entry_id) = 0;
 
   // Request to view an article by url.
-  scoped_ptr<ViewerHandle> ViewUrl(ViewRequestDelegate* delegate,
-                                   const GURL& url);
+  virtual scoped_ptr<ViewerHandle> ViewUrl(ViewRequestDelegate* delegate,
+                                           const GURL& url) = 0;
 
-  void AddObserver(DomDistillerObserver* observer);
-  void RemoveObserver(DomDistillerObserver* observer);
+  virtual void AddObserver(DomDistillerObserver* observer) = 0;
+  virtual void RemoveObserver(DomDistillerObserver* observer) = 0;
+
+ protected:
+  DomDistillerServiceInterface() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DomDistillerServiceInterface);
+};
+
+// Provide a view of the article list and ways of interacting with it.
+class DomDistillerService : public DomDistillerServiceInterface {
+ public:
+  DomDistillerService(scoped_ptr<DomDistillerStoreInterface> store,
+                      scoped_ptr<DistillerFactory> distiller_factory);
+  virtual ~DomDistillerService();
+
+  // DomDistillerServiceInterface implementation.
+  virtual syncer::SyncableService* GetSyncableService() const OVERRIDE;
+  virtual const std::string AddToList(
+      const GURL& url,
+      const ArticleAvailableCallback& article_cb) OVERRIDE;
+  virtual std::vector<ArticleEntry> GetEntries() const OVERRIDE;
+  virtual scoped_ptr<ArticleEntry> RemoveEntry(const std::string& entry_id)
+      OVERRIDE;
+  virtual scoped_ptr<ViewerHandle> ViewEntry(ViewRequestDelegate* delegate,
+                                             const std::string& entry_id)
+      OVERRIDE;
+  virtual scoped_ptr<ViewerHandle> ViewUrl(ViewRequestDelegate* delegate,
+                                           const GURL& url) OVERRIDE;
+  virtual void AddObserver(DomDistillerObserver* observer) OVERRIDE;
+  virtual void RemoveObserver(DomDistillerObserver* observer) OVERRIDE;
 
  private:
   void CancelTask(TaskTracker* task);