Add mojoPrivate.requireAsync method to chrome IDL.

Add unit tests for requireAsync.

R=mfoltz@chromium.org,sammc@chromium.org
CC=wez@chromium.org,haibinlu@chromium.org
BUG=

Review URL: https://codereview.chromium.org/862793003

Cr-Commit-Position: refs/heads/master@{#313403}

extensions/common/api/mojo_private.idl

@@ -14,6 +14,10 @@ namespace mojoPrivate {
         DOMString moduleName,
         optional DOMString[] dependencies,
         DefineCallback factory);
+
+    // Returns a promise that will resolve to an asynchronously
+    // loaded module.
+    [nocompile] static any requireAsync(DOMString name);
   };
 
 };

extensions/renderer/api/mojo_private/mojo_private_unittest.cc

@@ -45,4 +45,14 @@ TEST_F(MojoPrivateApiTest, DefineModuleDoesNotExist) {
                     "does not exist!"));
 }
 
+TEST_F(MojoPrivateApiTest, RequireAsync) {
+  ASSERT_NO_FATAL_FAILURE(
+      RunTest("mojo_private_unittest.js", "testRequireAsync"));
+}
+
+TEST_F(MojoPrivateApiTest, DefineAndRequire) {
+  ASSERT_NO_FATAL_FAILURE(
+      RunTest("mojo_private_unittest.js", "testDefineAndRequire"));
+}
+
 }  // namespace extensions

extensions/renderer/resources/mojo_private_custom_bindings.js

@@ -14,6 +14,10 @@ binding.registerCustomHook(function(bindingsAPI) {
   apiFunctions.setHandleRequest('define', function(name, deps, factory) {
     define(name, deps || [], factory);
   });
+
+  apiFunctions.setHandleRequest('requireAsync', function(moduleName) {
+    return requireAsync(moduleName);
+  });
 });
 
 exports.binding = binding.generate();

extensions/test/data/mojo_private_unittest.js

@@ -31,4 +31,24 @@ unittestBindings.exportTests([
     mojoPrivate.define('testModule', ['does not exist!'], test.fail);
     test.succeed();
   },
+
+  function testRequireAsync() {
+    mojoPrivate.requireAsync('mojo/public/js/codec').then(
+        test.callbackPass(function(codec) {
+          test.assertEq('function', typeof codec.Message);
+        }));
+  },
+
+  function testDefineAndRequire() {
+    mojoPrivate.define('testModule', ['dependency'],
+                       test.callbackPass(function(module) {
+      test.assertEq(12345, module.result);
+    }));
+    mojoPrivate.define('dependency', test.callbackPass(function() {
+      return {result: 12345};
+    }));
+    mojoPrivate.requireAsync('dependency').then(
+        test.callbackPass(),
+        test.fail);
+  }
 ], test.runTests, exports);