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::GetPageType(
    int handle,
    bool* success,
    content::PageType* page_type) {
  if (tab_tracker_->ContainsHandle(handle)) {
    NavigationController* tab = tab_tracker_->GetResource(handle);
    NavigationEntry* entry = tab->GetActiveEntry();
    *page_type = entry->GetPageType();
    *success = true;
    if (*page_type == content::PAGE_TYPE_NORMAL &&
        tab->GetWebContents()->ShowingInterstitialPage())
      *page_type = content::PAGE_TYPE_INTERSTITIAL;
  } else {
    *success = false;
    *page_type = content::PAGE_TYPE_NORMAL;
  }
}

void TestingAutomationProvider::GetPageType(
    int handle,
    bool* success,
    content::PageType* page_type) {
  if (tab_tracker_->ContainsHandle(handle)) {
    NavigationController* tab = tab_tracker_->GetResource(handle);
    NavigationEntry* entry = tab->GetActiveEntry();
    *page_type = entry->GetPageType();
    *success = true;
    if (*page_type == content::PAGE_TYPE_NORMAL &&
        tab->GetWebContents()->ShowingInterstitialPage())
      *page_type = content::PAGE_TYPE_INTERSTITIAL;
  } else {
    *success = false;
    *page_type = content::PAGE_TYPE_NORMAL;
  }
}
