Revert of First set of WebUSB layout tests with Mojo service mocks.

third_party/WebKit/LayoutTests/resources/mojo-helpers.js

Index: third_party/WebKit/LayoutTests/resources/mojo-helpers.js
diff --git a/third_party/WebKit/LayoutTests/resources/mojo-helpers.js b/third_party/WebKit/LayoutTests/resources/mojo-helpers.js
index aca02bc9b78c7375375d4a1a43c11a5e4d427eae..10350f7fc6da14d53e0c579956f578d7d414356b 100644
--- a/third_party/WebKit/LayoutTests/resources/mojo-helpers.js
+++ b/third_party/WebKit/LayoutTests/resources/mojo-helpers.js
@@ -6,26 +6,15 @@
 
 // Fix up the global window.define, since all baked-in Mojo modules expect to
 // find it there. This define() also returns a promise to the module.
-let define = (function(){
-  let moduleCache = new Map();
-
-  return function(name, deps, factory) {
-    let promise = moduleCache.get(name);
-    if (promise === undefined) {
-      // This promise must be cached as mojo.define will only call the factory
-      // function the first time the module is defined.
-      promise = new Promise(resolve => {
-        mojo.define(name, deps, (...modules) => {
-          let result = factory(...modules);
-          resolve(result);
-          return result;
-        });
-      });
-      moduleCache.set(name, promise);
-    }
-    return promise;
-  }
-})();
+function define(name, deps, factory) {
+  return new Promise(resolve => {
+    mojo.define(name, deps, (...modules) => {
+      let result = factory(...modules);
+      resolve(result);
+      return result;
+    });
+  });
+}
 
 // Returns a promise to an object that exposes common Mojo module interfaces.
 // Additional modules to load can be specified in the |modules| parameter. The