MAGETWO-36269: Create /mine APIs for CartManagement

 - Added /mine endpoint for placeOrder
 - Added api-functional test case to cover this endpoint

Author: marcozheng

app/code/Magento/Quote/etc/webapi.xml

@@ -59,6 +59,15 @@
             <parameter name="customerId" force="true">%customer_id%</parameter>
         </data>
     </route>
+    <route url="/V1/carts/mine/order" method="PUT">
+        <service class="Magento\Quote\Api\CartManagementInterface" method="placeOrder"/>
+        <resources>
+            <resource ref="self" />
+        </resources>
+        <data>
+            <parameter name="cartId" force="true">%cart_id%</parameter>
+        </data>
+    </route>
 
     <!-- Managing guest carts -->
 

dev/tests/api-functional/testsuite/Magento/Quote/Api/CartManagementTest.php

@@ -369,6 +369,41 @@ public function testPlaceOrder()
         $quote->delete();
     }
 
+    /**
+     * @magentoApiDataFixture Magento/Checkout/_files/quote_with_check_payment.php
+     */
+    public function testPlaceOrderForMyCart()
+    {
+        $this->_markTestAsRestOnly();
+
+        // get customer ID token
+        /** @var \Magento\Integration\Service\V1\CustomerTokenServiceInterface $customerTokenService */
+        $customerTokenService = $this->objectManager->create(
+            'Magento\Integration\Service\V1\CustomerTokenServiceInterface'
+        );
+        $token = $customerTokenService->createCustomerAccessToken('customer@example.com', 'password');
+
+        /** @var $quote \Magento\Quote\Model\Quote */
+        $quote = $this->objectManager->create('Magento\Quote\Model\Quote')->load('test_order_1', 'reserved_order_id');
+
+        $serviceInfo = [
+            'rest' => [
+                'resourcePath' => '/V1/carts/mine/order',
+                'httpMethod' => \Magento\Framework\Webapi\Rest\Request::HTTP_METHOD_PUT,
+                'token' => $token
+            ],
+        ];
+
+        $orderId = $this->_webApiCall($serviceInfo, []);
+
+        /** @var \Magento\Sales\Model\Order $order */
+        $order = $this->objectManager->create('Magento\Sales\Model\Order')->load($orderId);
+        $items = $order->getAllItems();
+        $this->assertCount(1, $items);
+        $this->assertEquals('Simple Product', $items[0]->getName());
+        $quote->delete();
+    }
+
     /**
      * Test to get my cart based on customer authentication token or session
      *