mock up of file contents in CompilerOutput

gistfile1.txt

diff --git a/packages/flutter_tools/lib/src/compile.dart b/packages/flutter_tools/lib/src/compile.dart
index 49e224c802..ff79346b68 100644
--- a/packages/flutter_tools/lib/src/compile.dart
+++ b/packages/flutter_tools/lib/src/compile.dart
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'package:meta/meta.dart';
 import 'package:package_config/package_config.dart';
@@ -61,9 +62,10 @@ class TargetModel {
 }
 
 class CompilerOutput {
-  const CompilerOutput(this.outputFilename, this.errorCount, this.sources);
+  const CompilerOutput(this.outputFilename, this.errorCount, this.sources, {this.fileContents});
 
   final String outputFilename;
+  final Uint8List fileContents;
   final int errorCount;
   final List<Uri> sources;
 }
@@ -78,6 +80,7 @@ class StdoutHandler {
     reset();
   }
 
+  final FileSystem _fileSystem;
   final Logger _logger;
 
   String boundaryKey;
@@ -87,8 +90,10 @@ class StdoutHandler {
 
   bool _suppressCompilerMessages;
   bool _expectSources;
+  bool _requestFileContents;
 
   void handler(String message) {
     const String kResultPrefix = 'result ';
     if (boundaryKey == null && message.startsWith(kResultPrefix)) {
       boundaryKey = message.substring(kResultPrefix.length);
@@ -106,6 +111,15 @@ class StdoutHandler {
         return;
       }
       final int spaceDelimiter = message.lastIndexOf(' ');
+      if (_requestFileContents) {
+        compilerOutput.complete(
+            CompilerOutput(
+                message.substring(boundaryKey.length + 1, spaceDelimiter),
+                int.parse(message.substring(spaceDelimiter + 1).trim()),
+                sources,
+                fileContents: _fileSystem.file(message.substring(boundaryKey.length + 1, spaceDelimiter)).readAsBytesSync()
+            ));
+        return;
+      }
       compilerOutput.complete(
           CompilerOutput(
               message.substring(boundaryKey.length + 1, spaceDelimiter),
@@ -136,11 +150,12 @@ class StdoutHandler {
 
   // This is needed to get ready to process next compilation result output,
   // with its own boundary key and new completer.
-  void reset({ bool suppressCompilerMessages = false, bool expectSources = true }) {
+  void reset({ bool suppressCompilerMessages = false, bool expectSources = true, bool requestFileContents = true }) {
     boundaryKey = null;
     compilerOutput = Completer<CompilerOutput>();
     _suppressCompilerMessages = suppressCompilerMessages;
     _expectSources = expectSources;
+    _requestFileContents = requestFileContents;
     state = StdoutState.CollectDiagnostic;
   }
 }
 @@ -750,7 +766,7 @@ class DefaultResidentCompiler implements ResidentCompiler {
   }
 
   Future<CompilerOutput> _compileExpression(_CompileExpressionRequest request) async {
-    _stdoutHandler.reset(suppressCompilerMessages: true, expectSources: false);
+    _stdoutHandler.reset(suppressCompilerMessages: true, expectSources: false, requestFileContents: true);
 
     // 'compile-expression' should be invoked after compiler has been started,
     // program was compiled.