Last power operation

Displays correct power operation time. In the case
that there has not been a power operation, 'not
available' is displayed.

Resolves openbmc/openbmc#2957

Tested: The GUI displayed 'not available' when it
    received a 0 value and the correct date when an
    epoch was recieved.

Signed-off-by: beccabroek <rebecca.shaw@ibm.com>
Change-Id: I9573a1cdcd31ba4c02888bd46d195c91fdb916a7
diff --git a/app/common/services/api-utils.js b/app/common/services/api-utils.js
index cfdd39f..37aacf6 100644
--- a/app/common/services/api-utils.js
+++ b/app/common/services/api-utils.js
@@ -653,6 +653,21 @@
                     }
                   });
         },
+        getLastPowerTime: function() {
+          return $http({
+                   method: 'GET',
+                   url: DataService.getHost() +
+                       '/xyz/openbmc_project/state/chassis0/attr/LastStateChangeTime',
+                   headers: {
+                     'Accept': 'application/json',
+                     'Content-Type': 'application/json'
+                   },
+                   withCredentials: true
+                 })
+              .then(function(response) {
+                return response.data;
+              });
+        },
         getLogs: function() {
           var deferred = $q.defer();
           $http({