refactor: use isDefined and isUndefined consistently

Fix any place that x == undefined or x != undefined
to use isUndefined and isDefined instead

Closes #4365

Author: lucastetreault

src/ngCookies/cookieWriter.js

@@ -20,7 +20,7 @@ function $$CookieWriter($document, $log, $browser) {
     options = options || {};
     expires = options.expires;
     path = angular.isDefined(options.path) ? options.path : cookiePath;
-    if (isUndefined(value)) {
+    if (angular.isUndefined(value)) {
       expires = 'Thu, 01 Jan 1970 00:00:00 GMT';
       value = '';
     }

src/ngMock/angular-mocks.js

@@ -87,7 +87,7 @@ angular.mock.$Browser = function() {
       if (fn.id === deferId) fnIndex = index;
     });
 
-    if (isDefined(fnIndex)) {
+    if (angular.isDefined(fnIndex)) {
       self.deferredFns.splice(fnIndex, 1);
       return true;
     }
@@ -462,7 +462,7 @@ angular.mock.$IntervalProvider = function() {
             if (fn.id === promise.$$intervalId) fnIndex = index;
           });
 
-          if (isDefined(fnIndex)) {
+          if (angular.isDefined(fnIndex)) {
             repeatFns.splice(fnIndex, 1);
           }
         }
@@ -504,7 +504,7 @@ angular.mock.$IntervalProvider = function() {
         if (fn.id === promise.$$intervalId) fnIndex = index;
       });
 
-      if (isDefined(fnIndex)) {
+      if (angular.isDefined(fnIndex)) {
         repeatFns[fnIndex].deferred.reject('canceled');
         repeatFns.splice(fnIndex, 1);
         return true;

src/ngResource/resource.js

@@ -17,7 +17,7 @@ function lookupDottedPath(obj, path) {
     throw $resourceMinErr('badmember', 'Dotted member path "@{0}" is invalid.', path);
   }
   var keys = path.split('.');
-  for (var i = 0, ii = keys.length; i < ii && isDefined(obj); i++) {
+  for (var i = 0, ii = keys.length; i < ii && angular.isDefined(obj); i++) {
     var key = keys[i];
     obj = (obj !== null) ? obj[key] : undefined;
   }

src/ngScenario/Scenario.js

@@ -293,7 +293,7 @@ _jQuery.fn.bindings = function(windowJquery, bindExp) {
   }
 
   function push(value) {
-    if (isUndefined(value)) {
+    if (angular.isUndefined(value)) {
       value = '';
     } else if (typeof value !== 'string') {
       value = angular.toJson(value);