[ServiceWorker] Tests for Cache

LayoutTests/http/tests/serviceworker/resources/worker-testharness.js

Index: LayoutTests/http/tests/serviceworker/resources/worker-testharness.js
diff --git a/LayoutTests/http/tests/serviceworker/resources/worker-testharness.js b/LayoutTests/http/tests/serviceworker/resources/worker-testharness.js
index 986c86a82ed7d8960380e258e78f03d5ccdd8bf8..73b4186c17308098ad12b0fe6afab1702ccec61e 100644
--- a/LayoutTests/http/tests/serviceworker/resources/worker-testharness.js
+++ b/LayoutTests/http/tests/serviceworker/resources/worker-testharness.js
@@ -72,3 +72,25 @@ importScripts('/resources/testharness.js');
       }
     });
 })();
+
+(function() {
+  var next_cache_index = 1;
+
+  // Returns a promise that resolves to a newly created Cache object. The
+  // returned Cache will be destroyed when |test| completes.
+  function create_temporary_cache(test, base_name) {
+    var uniquifier = base_name || String(++next_cache_index);
+    var cache_name = self.location.pathname + '/' + uniquifier;
+
+    test.add_cleanup(function() {
+        self.caches.delete(cache_name);
+      });
+
+    return self.caches.delete(cache_name)
+      .then(function() {
+          return self.caches.create(cache_name);
+        });
+  }
+
+  self.create_temporary_cache = create_temporary_cache;
+})();