Expose Cache Storage API in global window/worker scope

LayoutTests/http/tests/cachestorage/script-tests/cache-match.js

-importScripts('worker-testharness.js');
-importScripts('/resources/testharness-helpers.js');
-importScripts('override_assert_object_equals.js');
+if (self.importScripts) {
+    importScripts('/resources/testharness.js');
+    importScripts('/resources/testharness-helpers.js');
+    importScripts('../resources/test-helpers.js');
+}
 
 // A set of Request/Response pairs to be used with prepopulated_cache_test().
 var simple_entries = [
   {
     name: 'a',
     request: new Request('http://example.com/a'),
     response: new Response('')
   },
 
   {
@@ skipping 384 matching lines @@
               entries.vary_cookie_absent.response,
               entries.vary_wildcard.response
             ],
             'Cache.matchAll should honor "ignoreVary" parameter.');
         });
   }, 'Cache.matchAll with "ignoreVary" parameter');
 
 cache_test(function(cache) {
     var request = new Request('http://example.com');
     var response;
-    var request_url = new URL('simple.txt', location.href).href;
+    var request_url = new URL('../resources/simple.txt', location.href).href;
     return fetch(request_url)
       .then(function(fetch_result) {
           response = fetch_result;
           assert_equals(
             response.url, request_url,
             '[https://fetch.spec.whatwg.org/#dom-response-url] ' +
             'Reponse.url should return the URL of the response.');
           return cache.put(request, response.clone());
         })
       .then(function() {
           return cache.match(request.url);
         })
       .then(function(result) {
           assert_object_equals(
             result, response,
             'Cache.match should return a Response object that has the same ' +
             'properties as the stored response.');
           return cache.match(response.url);
         })
       .then(function(result) {
           assert_equals(
             result, undefined,
             'Cache.match should not match cache entry based on response URL.');
         });
   }, 'Cache.match with Request and Response objects with different URLs');
 
 cache_test(function(cache) {
-    var request_url = new URL('simple.txt', location.href).href;
+    var request_url = new URL('../resources/simple.txt', location.href).href;
     return fetch(request_url)
       .then(function(fetch_result) {
           return cache.put(new Request(request_url), fetch_result);
         })
       .then(function() {
           return cache.match(request_url);
         })
       .then(function(result) {
           return result.text();
         })
@@ skipping 41 matching lines @@
         });
       p = p.then(function() {
           assert_equals(Object.keys(hash).length, entries.length);
         });
 
       return p.then(function() {
           return test_function(cache, hash);
         });
     }, description);
 }
+
+done();