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::GetWindowForBrowser(int browser_handle,
                                                    bool* success,
                                                    int* handle) {
  *success = false;
  *handle = 0;

  if (browser_tracker_->ContainsHandle(browser_handle)) {
    Browser* browser = browser_tracker_->GetResource(browser_handle);
    gfx::NativeWindow win = browser->window()->GetNativeHandle();
    *handle = window_tracker_->Add(win);
    *success = true;
  }
}

void TestingAutomationProvider::GetWindowForBrowser(int browser_handle,
                                                    bool* success,
                                                    int* handle) {
  *success = false;
  *handle = 0;

  if (browser_tracker_->ContainsHandle(browser_handle)) {
    Browser* browser = browser_tracker_->GetResource(browser_handle);
    gfx::NativeWindow win = browser->window()->GetNativeHandle();
    *handle = window_tracker_->Add(win);
    *success = true;
  }
}
