Adds modularized promise functions to externs

Author: lourd

emcc.py

@@ -3355,13 +3355,14 @@ def modularize():
 
   src = '''
 function(%(EXPORT_NAME)s) {
-  return new Promise((returned_promise_resolve, returned_promise_reject) => {
-  
+  var returned_promise_resolve, returned_promise_reject;
+  var promise = new Promise((resolve, reject) => (returned_promise_resolve=resolve, returned_promise_reject=reject));
+
   %(EXPORT_NAME)s = %(EXPORT_NAME)s || {};
 
 %(src)s
 
-  });
+  return promise;
 }
 ''' % {
     'EXPORT_NAME': shared.Settings.EXPORT_NAME,

src/closure-externs/closure-externs.js

@@ -994,3 +994,11 @@ var threadInfoStruct;
 var selfThreadId;
 /** @suppress {duplicate} */
 var noExitRuntime;
+
+// These functions are declared in emcc.py but used in postamble.js; we need
+// to explicitly tell Closure Compiler about their existence since the
+// postamble is optimized independently
+/** @type {Function} */
+var returned_promise_resolve;
+/** @type {Function} */
+var returned_promise_reject;

src/postamble.js

@@ -63,7 +63,12 @@ if (memoryInitializer) {
     };
     var doBrowserLoad = function() {
       readAsync(memoryInitializer, applyMemoryInitializer, function() {
-        returned_promise_reject(new Error('could not load memory initializer ' + memoryInitializer));
+        var e = new Error('could not load memory initializer ' + memoryInitializer);
+#if MODULARIZE
+          returned_promise_reject(e);
+#else
+          throw e;
+#endif
       });
     };
 #if SUPPORT_BASE64_EMBEDDING

tests/test_browser.py

@@ -3353,10 +3353,10 @@ def test_minimal_runtime_modularize(self):
   @requires_sync_compilation
   def test_modularize(self):
     for opts in [
-      [], 
-      ['-O1'], 
-      ['-O2', '-profiling'], 
-      ['-O2'], 
+      [],
+      ['-O1'],
+      ['-O2', '-profiling'],
+      ['-O2'],
       ['-O2', '--closure', '1']
     ]:
       for args, code in [