Remove InstallTracker's extension installed, uninstalled observers.

chrome/browser/extensions/shared_module_service.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 CHROME_BROWSER_EXTENSIONS_SHARED_MODULE_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_SHARED_MODULE_SERVICE_H_
 
 #include <list>
 
-#include "chrome/browser/extensions/install_observer.h"
+#include "base/scoped_observer.h"
+#include "extensions/browser/extension_registry_observer.h"
 #include "extensions/common/manifest_handlers/shared_module_info.h"
 
 namespace content {
 class BrowserContext;
 }
 
 namespace extensions {
-
 class Extension;
 class ExtensionSet;
+class ExtensionRegistry;
 
-class SharedModuleService : public InstallObserver {
+class SharedModuleService : public ExtensionRegistryObserver {
  public:
   enum ImportStatus {
     // No imports needed.
     IMPORT_STATUS_OK,
 
     // Imports are needed, but can be satisfied (i.e., there are missing or
     // outdated imports for a webstore extension).
     IMPORT_STATUS_UNSATISFIED,
 
     // Imports are needed, and can't be satisfied (i.e., missing or outdated
     // imports for an extension not in the webstore).
     IMPORT_STATUS_UNRECOVERABLE
   };
 
   explicit SharedModuleService(content::BrowserContext* context);
   virtual ~SharedModuleService();
 
   // Checks an extension's imports. Imports that are not installed are stored
   // in |missing_modules|, and imports that are out of date are stored in
   // |outdated_modules|.
   ImportStatus CheckImports(
-      const extensions::Extension* extension,
+      const Extension* extension,
       std::list<SharedModuleInfo::ImportInfo>* missing_modules,
       std::list<SharedModuleInfo::ImportInfo>* outdated_modules);
 
   // Checks an extension's shared module imports to see if they are satisfied.
   // If they are not, this function adds the dependencies to the pending install
   // list if |extension| came from the webstore.
-  ImportStatus SatisfyImports(const extensions::Extension* extension);
+  ImportStatus SatisfyImports(const Extension* extension);
 
  private:
   // Returns a set of extensions that import a given extension.
   scoped_ptr<const ExtensionSet> GetDependentExtensions(
       const Extension* extension);
 
-  // Uninstalls shared modules that were only referenced by |extension|.
-  void PruneSharedModulesOnUninstall(const Extension* extension);
+  // ExtensionRegistryObserver implementation.
+  virtual void OnExtensionUninstalled(content::BrowserContext* browser_context,
+                                      const Extension* extension) OVERRIDE;
 
-  // InstallObserver implementation:
-  virtual void OnExtensionUninstalled(const Extension* extension) OVERRIDE;
-  virtual void OnShutdown() OVERRIDE;
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
+      extension_registry_observer_;
 
   // The context associated with this SharedModuleService.
-  content::BrowserContext* context_;
-
-  // Whether or not we are actively observing installs.
-  bool observing_;
+  content::BrowserContext* browser_context_;
 
   DISALLOW_COPY_AND_ASSIGN(SharedModuleService);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_SHARED_MODULE_SERVICE_H_