Add the 'cache' datatype to the clear-site-data WPT

third_party/WebKit/LayoutTests/external/wpt/clear-site-data/navigation.html

Index: third_party/WebKit/LayoutTests/external/wpt/clear-site-data/navigation.html
diff --git a/third_party/WebKit/LayoutTests/external/wpt/clear-site-data/navigation.html b/third_party/WebKit/LayoutTests/external/wpt/clear-site-data/navigation.html
index cd0f83e17f02567522624968d1ac62f029d126eb..7f006cc57c98878a011b19ac0615649a61fe36b5 100644
--- a/third_party/WebKit/LayoutTests/external/wpt/clear-site-data/navigation.html
+++ b/third_party/WebKit/LayoutTests/external/wpt/clear-site-data/navigation.html
@@ -11,11 +11,17 @@
       /** Ensures that all datatypes are nonempty. */
       function populateDatatypes() {
         return Promise.all(TestUtils.DATATYPES.map(function(datatype) {
-          return datatype.add().then(datatype.isEmpty().then(function(isEmpty) {
-            assert_false(
-                isEmpty,
-                datatype.name + " has to be nonempty before the test starts.");
-          }));
+          return new Promise(function(resolve, reject) {
+            datatype.add().then(function() {
+              datatype.isEmpty().then(function(isEmpty) {
+                assert_false(
+                    isEmpty,
+                    datatype.name +
+                        " has to be nonempty before the test starts.");
+                resolve();
+              });
+            });
+          });
         }));
       }