Added fixes for MR module loading.

Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I9b006ee2b566712ac2f62f8c0599054176f9bafc
Reviewed-on: https://chromium-review.googlesource.com/917307Reviewed-by: mark a. foltz <mfoltz@chromium.org>
Commit-Queue: John Williams <jrw@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538945}

chrome/browser/resources/media_router/extension/concat_js_modules.py

@@ -14,11 +14,12 @@ JSCompiler's --module flag.)
 
 import argparse
 import os.path
+import re
 
 def main():
   parser = argparse.ArgumentParser()
   parser.add_argument(
-      "--module-specs", nargs='+',
+      "--module-specs", nargs="+",
       help="List of module specifiations.")
   parser.add_argument(
       "--output-dir",
@@ -33,7 +34,7 @@ def main():
 
   # Read the prelude file, which contains code to be placed at the
   # start of each module.
-  with open(args.prelude_file, 'r') as prelude_in:
+  with open(args.prelude_file, "r") as prelude_in:
     prelude = prelude_in.read()
 
   # Loop over all specified modules, and simulaneously traverse the
@@ -42,10 +43,10 @@ def main():
   for spec in args.module_specs:
     # Split the module spec into a module name and a count of source
     # files to include in the module.
-    pre, sep, post = spec.partition('module=')
-    assert pre == ''
+    pre, sep, post = spec.partition("module=")
+    assert pre == ""
     assert sep
-    parts = post.split(':')
+    parts = post.split(":")
     module_name = parts[0]
     input_count = int(parts[1])
 
@@ -58,8 +59,26 @@ def main():
       for i in range(input_count):
         source_file = args.sources[source_index]
         source_index += 1
+        module_name = None
         with open(source_file, "r") as source_in:
-          module_out.write(source_in.read())
+          module_out.write("goog.scope(() => {\n")
+          # Copy input line by line.
+          for line in source_in:
+            m = re.match(r"goog\.module\('([^']+)'\);\n", line)
+            if m:
+              # Handle goog.module statements specially.
+              module_name = m.group(1)
+              module_out.write("let exports = {};\n")
+            else:
+              # Typical case: just copy the line verbatim.
+              module_out.write(line)
+          if module_name:
+            # Put exported names into the global namespace.  That's
+            # not now goog.module is supposed to work, but it's close
+            # enough.
+            module_out.write(
+                "__setGlobal('{}', exports);\n".format(module_name));
+          module_out.write("});\n")
 
   # Check that every source file has been appended to a module.
   if source_index != len(args.sources):

chrome/browser/resources/media_router/extension/prelude.js

@@ -2,11 +2,49 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-goog = {};
-goog.require = () => undefined;
-goog.provide = goog.require;
-goog.module = goog.require;
-goog.forwardDeclare = goog.require;
-goog.scope = body => {
-  body.call(window);
+// Implementation of JSCompiler intrinsics for use when JSCompiler is
+// not available.
+
+/**
+ * Sets the values of a global expression consisting of a
+ * dot-delimited list of identifiers.
+ */
+const __setGlobal = (name, value) => {
+  let parent = window;
+  const parts = name.split('.');
+  for (let i = 0; i < parts.length; i++) {
+    const part = parts[i];
+    if (i == parts.length - 1) {
+      parent[part] = value;
+    } else {
+      if (!parent[part]) {
+        parent[part] = {};
+      }
+      parent = parent[part];
+    }
+  }
+};
+
+const goog = {
+  provide(name) {
+    __setGlobal(name, {});
+  },
+
+  require(name) {
+    let parent = window;
+    name.split('.').forEach(part => {
+      parent = parent[part];
+    });
+    return parent;
+  },
+
+  module: {
+    declareLegacyNamespace() {},
+  },
+
+  forwardDeclare() {},
+
+  scope(body) {
+    body.call(window);
+  },
 };