Revert "Revert 266297 "1. Handle the case of empty embedder_extension_id...""

chrome/browser/guest_view/guest_view_base.h

-// Copyright 2013 The Chromium Authors. All rights reserved.
+// 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 CHROME_BROWSER_GUESTVIEW_GUESTVIEW_H_
-#define CHROME_BROWSER_GUESTVIEW_GUESTVIEW_H_
+#ifndef CHROME_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_
+#define CHROME_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_
 
 #include <queue>
 
 #include "base/memory/weak_ptr.h"
 #include "base/values.h"
 #include "content/public/browser/browser_plugin_guest_delegate.h"
 #include "content/public/browser/web_contents.h"
 
 class AdViewGuest;
 class WebViewGuest;
 struct RendererContentSettingRules;
 
-// A GuestView is the base class browser-side API implementation for a <*view>
-// tag. GuestView maintains an association between a guest WebContents and an
-// embedder WebContents. It receives events issued from the guest and relays
-// them to the embedder.
-class GuestView : public content::BrowserPluginGuestDelegate {
+// A GuestViewBase is the base class browser-side API implementation for a
+// <*view> tag. GuestViewBase maintains an association between a guest
+// WebContents and an embedder WebContents. It receives events issued from
+// the guest and relays them to the embedder.
+class GuestViewBase : public content::BrowserPluginGuestDelegate {
  public:
-  enum Type {
-    WEBVIEW,
-    ADVIEW,
-    UNKNOWN
-  };
-
   class Event {
    public:
-     Event(const std::string& name, scoped_ptr<base::DictionaryValue> args);
-     ~Event();
+    Event(const std::string& name, scoped_ptr<base::DictionaryValue> args);
+    ~Event();
 
     const std::string& name() const { return name_; }
 
     scoped_ptr<base::DictionaryValue> GetArguments();
 
    private:
     const std::string name_;
     scoped_ptr<base::DictionaryValue> args_;
   };
 
-  static Type GetViewTypeFromString(const std::string& api_type);
+  // Returns a *ViewGuest if this GuestView is of the given view type.
+  template <typename T>
+  T* As() {
+    if (GetViewType() == T::Type) {
+      return static_cast<T*>(this);
+    }
+    return NULL;
+  }
 
-  static GuestView* Create(content::WebContents* guest_web_contents,
-                           const std::string& embedder_extension_id,
-                           Type view_type);
+  static GuestViewBase* Create(content::WebContents* guest_web_contents,
+                               const std::string& embedder_extension_id,
+                               const std::string& view_type);
 
-  static GuestView* FromWebContents(content::WebContents* web_contents);
+  static GuestViewBase* FromWebContents(content::WebContents* web_contents);
 
-  static GuestView* From(int embedder_process_id, int instance_id);
+  static GuestViewBase* From(int embedder_process_id, int instance_id);
 
-  // For GuestViews, we create special guest processes, which host the
+  // For GuestViewBases, we create special guest processes, which host the
   // tag content separately from the main application that embeds the tag.
-  // A GuestView can specify both the partition name and whether the storage
+  // A GuestViewBase can specify both the partition name and whether the storage
   // for that partition should be persisted. Each tag gets a SiteInstance with
   // a specially formatted URL, based on the application it is hosted by and
   // the partition requested by it. The format for that URL is:
   // chrome-guest://partition_domain/persist?partition_name
   static bool GetGuestPartitionConfigForSite(const GURL& site,
                                              std::string* partition_domain,
                                              std::string* partition_name,
                                              bool* in_memory);
 
   // By default, JavaScript and images are enabled in guest content.
-  static void GetDefaultContentSettingRules(
-      RendererContentSettingRules* rules, bool incognito);
+  static void GetDefaultContentSettingRules(RendererContentSettingRules* rules,
+                                            bool incognito);
+
+  virtual const std::string& GetViewType() const = 0;

[Dan Beam, 2014/04/26 03:31:54]

why does this interface need to return a const std::string&, though?  why not a
const char* or std::string?

 
   virtual void Attach(content::WebContents* embedder_web_contents,
                       const base::DictionaryValue& args);
 
   content::WebContents* embedder_web_contents() const {
     return embedder_web_contents_;
   }
 
   // Returns the guest WebContents.
   content::WebContents* guest_web_contents() const {
     return guest_web_contents_;
   }
 
-  virtual Type GetViewType() const;
-
-  // Returns a WebViewGuest if this GuestView belongs to a <webview>.
-  virtual WebViewGuest* AsWebView() = 0;
-
-  // Returns an AdViewGuest if the GuestView belongs to an <adview>.
-  virtual AdViewGuest* AsAdView() = 0;
-
   // Returns whether this guest has an associated embedder.
   bool attached() const { return !!embedder_web_contents_; }
 
   // Returns the instance ID of the <*view> element.
   int view_instance_id() const { return view_instance_id_; }
 
   // Returns the instance ID of the guest WebContents.
   int guest_instance_id() const { return guest_instance_id_; }
 
   // Returns the extension ID of the embedder.
   const std::string& embedder_extension_id() const {
     return embedder_extension_id_;
   }
 
   // Returns whether this GuestView is embedded in an extension/app.
-  bool in_extension() const {
-    return !embedder_extension_id_.empty();
-  }
+  bool in_extension() const { return !embedder_extension_id_.empty(); }
 
   // Returns the user browser context of the embedder.
   content::BrowserContext* browser_context() const { return browser_context_; }
 
   // Returns the embedder's process ID.
   int embedder_render_process_id() const { return embedder_render_process_id_; }
 
  protected:
-  GuestView(content::WebContents* guest_web_contents,
-            const std::string& embedder_extension_id);
-  virtual ~GuestView();
+  GuestViewBase(content::WebContents* guest_web_contents,
+                const std::string& embedder_extension_id);
+  virtual ~GuestViewBase();
 
   // Dispatches an event |event_name| to the embedder with the |event| fields.
   void DispatchEvent(Event* event);
 
  private:
   void SendQueuedEvents();
 
   content::WebContents* const guest_web_contents_;
   content::WebContents* embedder_web_contents_;
   const std::string embedder_extension_id_;
   int embedder_render_process_id_;
   content::BrowserContext* const browser_context_;
   // |guest_instance_id_| is a profile-wide unique identifier for a guest
   // WebContents.
   const int guest_instance_id_;
   // |view_instance_id_| is an identifier that's unique within a particular
   // embedder RenderViewHost for a particular <*view> instance.
   int view_instance_id_;
 
   // This is a queue of Events that are destined to be sent to the embedder once
   // the guest is attached to a particular embedder.
   std::deque<linked_ptr<Event> > pending_events_;
 
   // This is used to ensure pending tasks will not fire after this object is
   // destroyed.
-  base::WeakPtrFactory<GuestView> weak_ptr_factory_;
+  base::WeakPtrFactory<GuestViewBase> weak_ptr_factory_;
 
-  DISALLOW_COPY_AND_ASSIGN(GuestView);
+  DISALLOW_COPY_AND_ASSIGN(GuestViewBase);
 };
 
-#endif  // CHROME_BROWSER_GUESTVIEW_GUESTVIEW_H_
+#endif  // CHROME_BROWSER_GUEST_VIEW_GUEST_VIEW_BASE_H_