[ServiceWorker] Tests for Cache

LayoutTests/http/tests/serviceworker/resources/worker-test-harness.js

Index: LayoutTests/http/tests/serviceworker/resources/worker-test-harness.js
diff --git a/LayoutTests/http/tests/serviceworker/resources/worker-test-harness.js b/LayoutTests/http/tests/serviceworker/resources/worker-test-harness.js
index 4129f8f8178f4f42f0aa135c383b31962ea1c99b..0407abde08fc7948a92beb6998acbb6615e7a090 100644
--- a/LayoutTests/http/tests/serviceworker/resources/worker-test-harness.js
+++ b/LayoutTests/http/tests/serviceworker/resources/worker-test-harness.js
@@ -110,3 +110,25 @@ function assert_promise_rejects(promise, code, description) {
       }
     });
 }
+
+(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;
+})();