Change mojo-helpers.js to support other test harnesses.

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

 /*
  * mojo-helpers contains extensions to testharness.js useful for consuming
  * and mocking Mojo services directly within test code.
  */
 'use strict';
 
+// 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.
+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
+// result will contain them, in the same order, in the |modules| field.
+function loadMojoModules(name, modules = []) {
+  return define('Mojo layout test module: ' + name, [
+      'mojo/public/js/core',
+      'mojo/public/js/router',
+      'mojo/public/js/support',
+      'content/public/renderer/service_provider',
+  ].concat(modules), (core, router, support, serviceProvider, ...rest) => {
+    return {
+      core: core,
+      router: router,
+      support: support,
+
+      // |serviceProvider| is a bit of a misnomer. It should probably be
+      // called |serviceRegistry|, so let's call it that here.
+      serviceRegistry: serviceProvider,
+
+      modules: rest,
+    };
+  });
+}
+
 // Runs a promise_test which depends on the Mojo system API modules available to
 // all layout tests. The test implementation function is called with an Object
 // that exposes common Mojo module interfaces.
 function mojo_test(func, name, properties) {
-  // Fix up the global window.define, since all baked-in Mojo modules expect to
-  // find it there.
-  window.define = mojo.define;
-
-  promise_test(() => {
-    return new Promise((resolve, reject) => {
-      define('Mojo layout test module: ' + name, [
-        'mojo/public/js/core',
-        'mojo/public/js/router',
-        'content/public/renderer/service_provider',
-      ], (core, router, serviceProvider) => {
-        try {
-          resolve(func({
-            core: core,
-            router: router,
-
-            // |serviceProvider| is a bit of a misnomer. It should probably be
-            // called |serviceRegistry|, so let's call it that here.
-            serviceRegistry: serviceProvider,
-          }));
-        } catch (e) {
-          reject(e);
-        }
-      });
-    });
-  }, name, properties);
+  promise_test(() => loadMojoModules(name).then(func), name, properties);
 }
 
-// Polls aggressively for a message to become available on a pipe.
+// Waits for a message to become available on a pipe.
 function mojo_wait_for_incoming_message(mojo, pipe) {
   return new Promise((resolve, reject) => {
-    let wait = () => {
-      let result = mojo.core.readMessage(pipe, 0);
-      if (result.result === mojo.core.RESULT_SHOULD_WAIT) {
-        setTimeout(wait);
+    mojo.support.asyncWait(pipe, mojo.core.HANDLE_SIGNAL_READABLE, result => {
+      if (result != mojo.core.RESULT_OK) {
+        reject(result);
         return;
       }
-
-      if (result.result !== mojo.core.RESULT_OK) {
-        reject(result.result);
+      let buffer, handles;
+      ({ result, buffer, handles } = mojo.core.readMessage(pipe, 0));
+      if (result !== mojo.core.RESULT_OK) {
+        reject(result);
         return;
       }
-
-      resolve({ buffer: result.buffer, handles: result.handles });
-    };
-
-    wait();
+      resolve({ buffer, handles });
+    });
   });
 };