[Extensions] Change renderer-side web accessible resource determination

extensions/renderer/extensions_renderer_client.h

 // 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 EXTENSIONS_RENDERER_EXTENSIONS_RENDERER_CLIENT_H_
 #define EXTENSIONS_RENDERER_EXTENSIONS_RENDERER_CLIENT_H_
 
+#include "extensions/common/extension_id.h"
+
 namespace extensions {
+class Extension;
 class Dispatcher;
 
 // Interface to allow the extensions module to make render-process-specific
 // queries of the embedder. Should be Set() once in the render process.
 //
 // NOTE: Methods that do not require knowledge of renderer concepts should be
 // added in ExtensionsClient (extensions/common/extensions_client.h) even if
 // they are only used in the renderer process.
 class ExtensionsRendererClient {
  public:
   virtual ~ExtensionsRendererClient() {}
 
   // Returns true if the current render process was launched incognito.
   virtual bool IsIncognitoProcess() const = 0;
 
   // Returns the lowest isolated world ID available to extensions.
   // Must be greater than 0. See blink::WebFrame::executeScriptInIsolatedWorld
   // (third_party/WebKit/public/web/WebFrame.h) for additional context.
   virtual int GetLowestIsolatedWorldId() const = 0;
 
   // Returns the associated Dispatcher.
   virtual Dispatcher* GetDispatcher() = 0;
 
+  // Notifies the client when an extension is added or removed.

[nasko, 2017/06/30 18:08:10]

Loaded/Unloaded? I can have an extension added to my profile but uncheck the
enabled box, which will unload it, right? Also, those are invoked from
OnLoaded/OnUnloaded, which will keep them consistent in terminology.

[Devlin, 2017/07/06 00:40:39]

I went back and forth on this, because this is in the renderer process, which
only has knowledge of loaded extensions.  But, sure.

+  // TODO(devlin): Make a RendererExtensionRegistryObserver?
+  virtual void OnExtensionAdded(const Extension& extension) {}
+  virtual void OnExtensionRemoved(const ExtensionId& extension) {}
+
   // Returns the single instance of |this|.
   static ExtensionsRendererClient* Get();
 
   // Initialize the single instance.
   static void Set(ExtensionsRendererClient* client);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_RENDERER_EXTENSIONS_RENDERER_CLIENT_H_