Use trackCacheDependencies for performance speedup

lib/src/analyzer/context.dart

Index: lib/src/analyzer/context.dart
diff --git a/lib/src/analyzer/context.dart b/lib/src/analyzer/context.dart
index 2bb9f7b2abce953c161c76f093371bc53e11ecd8..945e29d53b1e67d847dca26f266913a701a57fc0 100644
--- a/lib/src/analyzer/context.dart
+++ b/lib/src/analyzer/context.dart
@@ -142,7 +142,9 @@ AnalysisContext createAnalysisContextWithSources(AnalyzerOptions options,
 /// Creates an analysis context that contains our restricted typing rules.
 AnalysisContextImpl createAnalysisContext() {
   var res = AnalysisEngine.instance.createAnalysisContext();
-  res.analysisOptions = new AnalysisOptionsImpl()..strongMode = true;
+  res.analysisOptions = new AnalysisOptionsImpl()
+    ..strongMode = true
+    ..trackCacheDependencies = false;
   return res;
 }
 
@@ -188,7 +190,9 @@ DirectoryBasedDartSdk _createDirectoryBasedDartSdk(String sdkPath) {
   var sdk = new DirectoryBasedDartSdk(
       new JavaFile(sdkPath), /*useDart2jsPaths:*/ true);
   sdk.useSummary = true;
-  sdk.analysisOptions = new AnalysisOptionsImpl()..strongMode = true;
+  sdk.analysisOptions = new AnalysisOptionsImpl()
+    ..strongMode = true
+    ..trackCacheDependencies = false;

[Jennifer Messerly, 2016/06/13 18:21:11]

Not sure if this matters for SDK context?

[scheglov, 2016/06/13 18:23:28]

SDK context results are served from summary, and we don't set dependencies for
them anyway.

   return sdk;
 }