Support native extensions for analysis and docgen.

pkg/compiler/lib/src/dart2js.dart

Index: pkg/compiler/lib/src/dart2js.dart
diff --git a/pkg/compiler/lib/src/dart2js.dart b/pkg/compiler/lib/src/dart2js.dart
index d034f3df1b4900d708641e003bad3c8e6500edde..4bf3baf3d3a0e5451cfd46e5230564b189ac1d81 100644
--- a/pkg/compiler/lib/src/dart2js.dart
+++ b/pkg/compiler/lib/src/dart2js.dart
@@ -115,6 +115,7 @@ Future compile(List<String> argv) {
   bool analyzeOnly = false;
   bool analyzeAll = false;
   bool enableAsyncAwait = false;
+  bool allowNativeExtensions = false;
   bool trustTypeAnnotations = false;
   bool checkedMode = false;
   // List of provided options that imply that output is expected.
@@ -195,6 +196,11 @@ Future compile(List<String> argv) {
     passThrough(argument);
   }
 
+  setAllowNativeExtensions(String argument) {
+    allowNativeExtensions = true;
+    passThrough(argument);
+  }
+
   setVerbose(_) {
     diagnosticHandler.verbose = true;
     passThrough('--verbose');
@@ -324,6 +330,7 @@ Future compile(List<String> argv) {
     new OptionHandler('--show-package-warnings', passThrough),
     new OptionHandler('--csp', passThrough),
     new OptionHandler('--enable-async', setEnableAsync),
+    new OptionHandler('--allow-native-extensions', setAllowNativeExtensions),
     new OptionHandler('-D.+=.*', addInEnvironment),
 
     // The following two options must come last.
@@ -384,9 +391,15 @@ Future compile(List<String> argv) {
         api.Diagnostic.INFO);
   }
   if (analyzeAll) analyzeOnly = true;
-  if (enableAsyncAwait && !analyzeOnly) {
-    helpAndFail("Option '--enable-async' is currently only supported in "
-                "combination with the '--analyze-only' option.");
+  if (!analyzeOnly) {
+    if (enableAsyncAwait) {
+      helpAndFail("Option '--enable-async' is currently only supported in "
+                  "combination with the '--analyze-only' option.");
+    }
+    if (allowNativeExtensions) {
+      helpAndFail("Option '--allow-native-extensions' is only supported in "
+                  "combination with the '--analyze-only' option.");
+    }
   }
 
   diagnosticHandler.info('Package root is $packageRoot');