Code:  void ExtensionUninstaller::Run() {
   const extensions::Extension* extension =
      extensions::ExtensionSystem::Get(profile_)->extension_service()->
          GetInstalledExtension(app_id_);
   if (!extension) {
     CleanUp();
     return;
  }
  controller_->OnShowChildDialog();
  dialog_.reset(extensions::ExtensionUninstallDialog::Create(
      profile_, controller_->GetAppListWindow(), this));
  dialog_->ConfirmUninstall(extension,
                            extensions::UNINSTALL_REASON_USER_INITIATED);
}

Vulnerability Type: DoS 
CWE ID: 
Summary: Multiple unspecified vulnerabilities in Google Chrome before 32.0.1700.76 on Windows and before 32.0.1700.77 on Mac OS X and Linux allow attackers to cause a denial of service or possibly have other impact via unknown vectors.
Commit Message: [Extensions] Add GetInstalledExtension() method to ExtensionRegistry

This CL adds GetInstalledExtension() method to ExtensionRegistry and
uses it instead of deprecated ExtensionService::GetInstalledExtension()
in chrome/browser/ui/app_list/.

Part of removing the deprecated GetInstalledExtension() call
from the ExtensionService.

BUG=489687

Review URL: https://codereview.chromium.org/1130353010

Cr-Commit-Position: refs/heads/master@{#333036}