dart2js: Add a header to the output of the startup emitter.

pkg/compiler/lib/src/js_emitter/startup_emitter/model_emitter.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.js_emitter.startup_emitter.model_emitter;
 
 import 'dart:convert' show JsonEncoder;
 
 import '../../common.dart';
 
@@ skipping 16 matching lines @@
     JavaScriptBackend,
     Namer,
     ConstantEmitter;
 
 import '../../util/util.dart' show
     NO_LOCATION_SPANNABLE;
 
 import '../../util/uri_extras.dart' show
     relativize;
 
+import '../headers.dart';
 import '../js_emitter.dart' show AstContainer, NativeEmitter;
 
 import 'package:js_runtime/shared/embedded_names.dart' show
     CLASS_FIELDS_EXTRACTOR,
     CLASS_ID_EXTRACTOR,
     CREATE_NEW_ISOLATE,
     DEFERRED_INITIALIZED,
     DEFERRED_LIBRARY_URIS,
     DEFERRED_LIBRARY_HASHES,
     GET_TYPE_FROM_NAME,
@@ skipping 164 matching lines @@
 
     if (compiler.deferredMapUri != null) {
       writeDeferredMap();
     }
     
     // Return the total program size.
     return outputBuffers.values.fold(0, (a, b) => a + b.length);
   }
 
   /// Generates a simple header that provides the compiler's build id.
-  String buildGeneratedBy(compiler) {
-    var suffix = '';
-    if (compiler.hasBuildId) suffix = ' version: ${compiler.buildId}';
-    return '// Generated by dart2js (fast startup), '
-        'the Dart to JavaScript compiler$suffix.\n';
+  js.Comment buildGeneratedBy() {
+    String flavor = compiler.useContentSecurityPolicy
+        ? 'fast startup, CSP'
+        : 'fast startup';
+    return new js.Comment(generatedBy(compiler, flavor: flavor));
   }
 
   /// Writes all deferred fragment's code into files.
   ///
   /// Returns a map from fragment to its hashcode (as used for the deferred
   /// library code).
   ///
   /// Updates the shared [outputBuffers] field with the output.
   Map<DeferredFragment, String> writeDeferredFragments(
       Map<DeferredFragment, js.Expression> fragmentsCode) {
@@ skipping 15 matching lines @@
     if (shouldGenerateSourceMap) {
       lineColumnCollector = new LineColumnCollector();
       codeOutputListeners = <CodeOutputListener>[lineColumnCollector];
     }
 
     CodeOutput mainOutput = new StreamCodeOutput(
             compiler.outputProvider('', 'js'),
             codeOutputListeners);
     outputBuffers[fragment] = mainOutput;
 
-    mainOutput.addBuffer(js.prettyPrint(code, compiler,
+    js.Program program = new js.Program([
+        buildGeneratedBy(),
+        new js.Comment(HOOKS_API_USAGE),
+        code]);
+
+    mainOutput.addBuffer(js.prettyPrint(program, compiler,
         monitor: compiler.dumpInfoTask));
 
     if (shouldGenerateSourceMap) {
       mainOutput.add(
           generateSourceMapTag(compiler.sourceMapUri, compiler.outputUri));
     }
 
     mainOutput.close();
 
     if (shouldGenerateSourceMap) {
@@ skipping 28 matching lines @@
 
     // The [code] contains the function that must be invoked when the deferred
     // hunk is loaded.
     // That function must be in a map from its hashcode to the function. Since
     // we don't know the hash before we actually emit the code we store the
     // function in a temporary field first:
     //
     //   deferredInitializer.current = <pretty-printed code>;
     //   deferredInitializer[<hash>] = deferredInitializer.current;
 
-    output.add('\n${deferredInitializersGlobal}.current = ');
+    js.Program program = new js.Program([
+        buildGeneratedBy(),
+        js.js.statement('$deferredInitializersGlobal.current = #', code)]);
 
-    output.addBuffer(js.prettyPrint(code, compiler,
+    output.addBuffer(js.prettyPrint(program, compiler,
         monitor: compiler.dumpInfoTask));
 
     // Make a unique hash of the code (before the sourcemaps are added)
     // This will be used to retrieve the initializing function from the global
     // variable.
     String hash = hasher.getHash();
 
     // Now we copy the deferredInitializer.current into its correct hash.
     output.add('\n${deferredInitializersGlobal}["$hash"] = '
         '${deferredInitializersGlobal}.current');
@@ skipping 66 matching lines @@
     // Json does not support comments, so we embed the explanation in the
     // data.
     mapping["_comment"] = "This mapping shows which compiled `.js` files are "
         "needed for a given deferred library import.";
     mapping.addAll(compiler.deferredLoadTask.computeDeferredMap());
     compiler.outputProvider(compiler.deferredMapUri.path, 'deferred_map')
       ..add(const JsonEncoder.withIndent("  ").convert(mapping))
       ..close();
   }
 }