Introduce background.scripts feature for extension manifests.

This optimizes for the common use case where background pages
just include a reference to one or more script files and no
additional HTML.

BUG=107791


Review URL: http://codereview.chromium.org/9150008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@117110 0039d316-1c4b-4281-b951-d872f2087c98
void ShowBalloon(const Extension* extension, Profile* profile) {
  string16 message = l10n_util::GetStringFUTF16(
      extension->is_app() ?  IDS_BACKGROUND_CRASHED_APP_BALLOON_MESSAGE :
      IDS_BACKGROUND_CRASHED_EXTENSION_BALLOON_MESSAGE,
      UTF8ToUTF16(extension->name()));
  string16 content_url = DesktopNotificationService::CreateDataUrl(
      extension->GetIconURL(Extension::EXTENSION_ICON_SMALLISH,
                            ExtensionIconSet::MATCH_BIGGER),
      string16(), message, WebKit::WebTextDirectionDefault);
  Notification notification(
      extension->url(), GURL(content_url), string16(), string16(),
      new CrashNotificationDelegate(profile, extension));
  g_browser_process->notification_ui_manager()->Add(notification, profile);
}

void ShowBalloon(const Extension* extension, Profile* profile) {
  string16 message = l10n_util::GetStringFUTF16(
      extension->is_app() ?  IDS_BACKGROUND_CRASHED_APP_BALLOON_MESSAGE :
      IDS_BACKGROUND_CRASHED_EXTENSION_BALLOON_MESSAGE,
      UTF8ToUTF16(extension->name()));
  string16 content_url = DesktopNotificationService::CreateDataUrl(
      extension->GetIconURL(Extension::EXTENSION_ICON_SMALLISH,
                            ExtensionIconSet::MATCH_BIGGER),
      string16(), message, WebKit::WebTextDirectionDefault);
  Notification notification(
      extension->url(), GURL(content_url), string16(), string16(),
      new CrashNotificationDelegate(profile, extension));
  g_browser_process->notification_ui_manager()->Add(notification, profile);
}
