tools/patches/flutter-flutter/403337ebb893380101d1fa9cc435ce9b6cfeb22c.patch

diff --git a/packages/flutter_tools/lib/src/compile.dart b/packages/flutter_tools/lib/src/compile.dart
index 5f936715f..702101c9d 100644
--- a/packages/flutter_tools/lib/src/compile.dart
+++ b/packages/flutter_tools/lib/src/compile.dart
@@ -57,12 +57,15 @@ class TargetModel {
 }

 class CompilerOutput {
-  const CompilerOutput(this.outputFilename, this.errorCount);
+  const CompilerOutput(this.outputFilename, this.errorCount, this.sources);

   final String outputFilename;
   final int errorCount;
+  final List<Uri> sources;
 }

+enum StdoutState { CollectDiagnostic, CollectDependencies }
+
 /// Handles stdin/stdout communication with the frontend server.
 class StdoutHandler {
   StdoutHandler({this.consumer = printError}) {
@@ -72,30 +75,54 @@ class StdoutHandler {
   bool compilerMessageReceived = false;
   final CompilerMessageConsumer consumer;
   String boundaryKey;
+  StdoutState state = StdoutState.CollectDiagnostic;
   Completer<CompilerOutput> compilerOutput;
+  final List<Uri> sources = <Uri>[];

   bool _suppressCompilerMessages;

   void handler(String message) {
+    printTrace('-> $message');
     const String kResultPrefix = 'result ';
     if (boundaryKey == null && message.startsWith(kResultPrefix)) {
       boundaryKey = message.substring(kResultPrefix.length);
     } else if (message.startsWith(boundaryKey)) {
-      if (message.length <= boundaryKey.length) {
-        compilerOutput.complete(null);
-        return;
+      if (state == StdoutState.CollectDiagnostic) {
+        state = StdoutState.CollectDependencies;
+      } else {
+        if (message.length <= boundaryKey.length) {
+          compilerOutput.complete(null);
+          return;
+        }
+        final int spaceDelimiter = message.lastIndexOf(' ');
+        compilerOutput.complete(
+            CompilerOutput(
+                message.substring(boundaryKey.length + 1, spaceDelimiter),
+                int.parse(message.substring(spaceDelimiter + 1).trim()),
+                sources));
       }
-      final int spaceDelimiter = message.lastIndexOf(' ');
-      compilerOutput.complete(
-        CompilerOutput(
-          message.substring(boundaryKey.length + 1, spaceDelimiter),
-          int.parse(message.substring(spaceDelimiter + 1).trim())));
-    } else if (!_suppressCompilerMessages) {
-      if (compilerMessageReceived == false) {
-        consumer('\nCompiler message:');
-        compilerMessageReceived = true;
+    } else {
+      if (state == StdoutState.CollectDiagnostic) {
+        if (!_suppressCompilerMessages) {
+          if (compilerMessageReceived == false) {
+            consumer('\nCompiler message:');
+            compilerMessageReceived = true;
+          }
+          consumer(message);
+        }
+      } else {
+        assert(state == StdoutState.CollectDependencies);
+        switch (message[0]) {
+          case '+':
+            sources.add(Uri.parse(message.substring(1)));
+            break;
+          case '-':
+            sources.remove(Uri.parse(message.substring(1)));
+            break;
+          default:
+            printTrace('Unexpected prefix for $message uri - ignoring');
+        }
       }
-      consumer(message);
     }
   }

@@ -106,6 +133,7 @@ class StdoutHandler {
     compilerMessageReceived = false;
     compilerOutput = Completer<CompilerOutput>();
     _suppressCompilerMessages = suppressCompilerMessages;
+    state = StdoutState.CollectDiagnostic;
   }
 }

@@ -200,7 +228,7 @@ class KernelCompiler {

       if (await fingerprinter.doesFingerprintMatch()) {
         printTrace('Skipping kernel compilation. Fingerprint match.');
-        return CompilerOutput(outputFilePath, 0);
+        return CompilerOutput(outputFilePath, 0, /* sources */ null);
       }
     }

@@ -453,10 +481,13 @@ class ResidentCompiler {
         ? _mapFilename(request.mainPath, packageUriMapper) + ' '
         : '';
     _server.stdin.writeln('recompile $mainUri$inputKey');
+    printTrace('<- recompile $mainUri$inputKey');
     for (String fileUri in request.invalidatedFiles) {
       _server.stdin.writeln(_mapFileUri(fileUri, packageUriMapper));
+      printTrace('<- ${_mapFileUri(fileUri, packageUriMapper)}');
     }
     _server.stdin.writeln(inputKey);
+    printTrace('<- $inputKey');

     return _stdoutHandler.compilerOutput.future;
   }
@@ -546,6 +577,7 @@ class ResidentCompiler {
       .listen((String message) { printError(message); });

     _server.stdin.writeln('compile $scriptUri');
+    printTrace('<- compile $scriptUri');

     return _stdoutHandler.compilerOutput.future;
   }
@@ -598,6 +630,7 @@ class ResidentCompiler {
   void accept() {
     if (_compileRequestNeedsConfirmation) {
       _server.stdin.writeln('accept');
+      printTrace('<- accept');
     }
     _compileRequestNeedsConfirmation = false;
   }
@@ -621,6 +654,7 @@ class ResidentCompiler {
     }
     _stdoutHandler.reset();
     _server.stdin.writeln('reject');
+    printTrace('<- reject');
     _compileRequestNeedsConfirmation = false;
     return _stdoutHandler.compilerOutput.future;
   }
@@ -630,6 +664,7 @@ class ResidentCompiler {
   /// kernel file.
   void reset() {
     _server?.stdin?.writeln('reset');
+    printTrace('<- reset');
   }

   String _mapFilename(String filename, PackageUriMapper packageUriMapper) {
diff --git a/packages/flutter_tools/lib/src/devfs.dart b/packages/flutter_tools/lib/src/devfs.dart
index 7940e8bb0..9e8b9bd45 100644
--- a/packages/flutter_tools/lib/src/devfs.dart
+++ b/packages/flutter_tools/lib/src/devfs.dart
@@ -557,6 +557,8 @@ class DevFS {
       outputPath:  dillOutputPath ?? getDefaultApplicationKernelPath(trackWidgetCreation: trackWidgetCreation),
       packagesFilePath : _packagesFilePath,
     );
+    // list of sources that needs to be monitored are in [compilerOutput.sources]
+    //
     // Don't send full kernel file that would overwrite what VM already
     // started loading from.
     if (!bundleFirstUpload) {