Find SDK properly when analyzing files in package mode.

pkg/analyzer_cli/lib/src/package_analyzer.dart

Index: pkg/analyzer_cli/lib/src/package_analyzer.dart
diff --git a/pkg/analyzer_cli/lib/src/package_analyzer.dart b/pkg/analyzer_cli/lib/src/package_analyzer.dart
index 51cacf2a13c421697a1a35e62f59265d221c6ef3..3b53b3f7e304315aaab8c1699cdf4bf12a66f672 100644
--- a/pkg/analyzer_cli/lib/src/package_analyzer.dart
+++ b/pkg/analyzer_cli/lib/src/package_analyzer.dart
@@ -15,6 +15,7 @@ import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/context/context.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
+import 'package:analyzer/src/generated/java_io.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 import 'package:analyzer/src/generated/sdk_io.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ -341,7 +342,8 @@ class PackageAnalyzer {
   }
 
   void _createContext() {
-    DirectoryBasedDartSdk sdk = DirectoryBasedDartSdk.defaultSdk;
+    DirectoryBasedDartSdk sdk =
+        new DirectoryBasedDartSdk(new JavaFile(options.dartSdkPath));
 
     // Create the context.
     context = AnalysisEngine.instance.createAnalysisContext();