--install-chrome-app opens new tab in existing window.

BUG=341353

Review URL: https://codereview.chromium.org/276263004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269755 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/apps/install_chrome_app.cc

@@ -41,6 +41,7 @@ void NavigateToUrlWithAccountsReferrer(const GURL& url) {
 
   chrome::NavigateParams params(
       browser, url, content::PAGE_TRANSITION_AUTO_TOPLEVEL);
+  params.disposition = NEW_FOREGROUND_TAB;
   params.window_action = chrome::NavigateParams::SHOW_WINDOW;
   params.referrer = content::Referrer();
   params.referrer.url = GURL(kAccountsUrl);