Add initial support for parts to the incremental kernel generator.

pkg/front_end/lib/src/incremental_resolved_ast_generator_impl.dart

Index: pkg/front_end/lib/src/incremental_resolved_ast_generator_impl.dart
diff --git a/pkg/front_end/lib/src/incremental_resolved_ast_generator_impl.dart b/pkg/front_end/lib/src/incremental_resolved_ast_generator_impl.dart
index 56050d51576561c0063ffa2b8206aca7c2a65f6f..0776d802ab59214044ac37e9762c3bfdf9190831 100644
--- a/pkg/front_end/lib/src/incremental_resolved_ast_generator_impl.dart
+++ b/pkg/front_end/lib/src/incremental_resolved_ast_generator_impl.dart
@@ -4,6 +4,7 @@
 
 import 'dart:async';
 
+import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
@@ -73,15 +74,34 @@ class IncrementalResolvedAstGeneratorImpl
     // the data from the summary.  TODO(paulberry): fix this.
     _fileRepository.store(Uri.parse('dart:core'), '');
     for (var libraryCycle in graph.topologicallySortedCycles) {
-      for (var uri in libraryCycle.libraries.keys) {
-        var contents =
-            await _options.fileSystem.entityForUri(uri).readAsString();
-        _fileRepository.store(uri, contents);
+      for (var libraryUri in libraryCycle.libraries.keys) {
+        var libraryNode = libraryCycle.libraries[libraryUri];
+        var libraryContents =
+            await _options.fileSystem.entityForUri(libraryUri).readAsString();
+        _fileRepository.store(libraryUri, libraryContents);
+        for (var partUri in libraryNode.parts) {
+          var partContents =
+              await _options.fileSystem.entityForUri(partUri).readAsString();
+          _fileRepository.store(partUri, partContents);
+        }
       }
-      for (var uri in libraryCycle.libraries.keys) {
-        var result = await _driver.getResult(_fileRepository.pathForUri(uri));
+      for (var libraryUri in libraryCycle.libraries.keys) {
+        var libraryNode = libraryCycle.libraries[libraryUri];
+        var result = await _driver.getResult(_fileRepository.pathForUri(libraryUri));
         // TODO(paulberry): handle errors.
-        libraries[uri] = new ResolvedLibrary(result.unit);
+        var definingCompilationUnit = result.unit;
+        var partUnits = <Uri, CompilationUnit>{};
+        for (var partUri in libraryNode.parts) {
+          // Really we ought to have a driver API that lets us request a
+          // specific part of a given library.  Otherwise we will run into
+          // problems if a part is included in multiple libraries.
+          // TODO(paulberry): address this.
+          var partResult = await _driver.getResult(_fileRepository.pathForUri(partUri));
+          // TODO(paulberry): handle errors.
+          partUnits[partUri] = partResult.unit;
+        }
+        libraries[libraryUri] =
+            new ResolvedLibrary(definingCompilationUnit, partUnits);
       }
     }
     _driver.addFile(_fileRepository.pathForUri(_source));
@@ -246,7 +266,9 @@ class _SourceFactoryProxy implements SourceFactory {
   Source resolveUri(Source containingSource, String containedUri) {
     // TODO(paulberry): re-use code from dependency_grapher_impl, and support
     // SDK URI resolution logic.
-    var absoluteUri = containingSource.uri.resolve(containedUri);
+    var absoluteUri = containingSource == null

[danrubel, 2017/01/19 20:06:39]

Is absoluteUri dynamic? IOW, will absoluteUri be a String if containingSource is
null, but a Uri if containingSource is not null? That feels a little awkward too
me. Perhaps change

    containingSource.uri.resolve(containedUri);
to
    containingSource.uri.resolve(containedUri).toString();

so that absoluteUri is always a string?

It would also be nicer to pass around instances of Uri rather than String, then
forUri(...) can accept a Uri rather than always having to call Uri.parse.  

That said there may be larger API issues compelling you to pass around Strings
rather than Uris, so entirely up to you how this should be handled.

[Paul Berry, 2017/01/19 20:29:46]

Whoops, thanks for catching this.  I took your suggestion of changing to
`containingSource.uri.resolve(containedUri).toString()`.

You guessed correctly that there are larger API issues compelling me to pass
around Strings.  Specifically the fact that this is a proxy object to interface
with existing analyzer code that deals with strings.  In the long run I hope to
get rid of these proxies entirely, and in the code I'm writing to replace them,
I'm trying to use URIs more consistently.

+        ? containedUri
+        : containingSource.uri.resolve(containedUri);
     return forUri(absoluteUri.toString());
   }