MAGETWO-52478: CreateOnlineCreditMemoBraintreePaypalTest is failing on closing popup window

- Fix for checkout from shopping cart

Author: rliukshyn

dev/tests/functional/tests/app/Magento/Braintree/Test/TestStep/CheckoutWithPaypalFromCartStep.php

@@ -37,7 +37,7 @@ public function __construct(CheckoutCart $checkoutCart)
     public function run()
     {
         $this->checkoutCart->open();
-        $this->checkoutCart->getCartBlock()->waitCartContainerLoading();
+        $this->checkoutCart->getTotalsBlock()->waitForUpdatedTotals();
         $currentWindow = $this->checkoutCart->getCartBlock()
             ->braintreePaypalCheckout();
         $this->checkoutCart->getBraintreePaypalBlock()->process($currentWindow);

dev/tests/functional/tests/app/Magento/Checkout/Test/Block/Cart/Totals.php

@@ -247,8 +247,7 @@ public function isVisibleShippingPriceBlock()
      */
     public function waitForUpdatedTotals()
     {
-        // Code under may use JavaScript delay at this point as well.
-        sleep(1);
+        $this->waitForElementVisible($this->blockWaitElement);
         $this->waitForElementNotVisible($this->blockWaitElement);
     }