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 TestingAutomationProvider::WaitForNotificationCount(
    Browser* browser,
    DictionaryValue* args,
    IPC::Message* reply_message) {
  int count;
  if (!args->GetInteger("count", &count)) {
    AutomationJSONReply(this, reply_message)
        .SendError("'count' missing or invalid.");
    return;
  }
  new OnNotificationBalloonCountObserver(this, reply_message, count);
}

void TestingAutomationProvider::WaitForNotificationCount(
    Browser* browser,
    DictionaryValue* args,
    IPC::Message* reply_message) {
  int count;
  if (!args->GetInteger("count", &count)) {
    AutomationJSONReply(this, reply_message)
        .SendError("'count' missing or invalid.");
    return;
  }
  new OnNotificationBalloonCountObserver(this, reply_message, count);
}
