Conditionally enable SDK summaries in server

pkg/analyzer/lib/src/generated/sdk.dart

Index: pkg/analyzer/lib/src/generated/sdk.dart
diff --git a/pkg/analyzer/lib/src/generated/sdk.dart b/pkg/analyzer/lib/src/generated/sdk.dart
index 6f50b44c1185a0d6cbcbc8b44c08f597c511b899..feadee663b33a1783290a16d8c90971a96027ec5 100644
--- a/pkg/analyzer/lib/src/generated/sdk.dart
+++ b/pkg/analyzer/lib/src/generated/sdk.dart
@@ -124,12 +124,7 @@ class DartSdkManager {
    */
   DartSdk getSdkForOptions(AnalysisOptions options) {
     int encoding = options.encodeCrossContextOptions();
-    DartSdk sdk = sdkMap[encoding];
-    if (sdk == null) {
-      sdk = sdkCreator(options);
-      sdkMap[encoding] = sdk;
-    }
-    return sdk;
+    return sdkMap.putIfAbsent(encoding, () => sdkCreator(options));

[Brian Wilkerson, 2016/06/01 04:16:51]

This is just code clean-up. I'm happy to back it out if you like.

[pquitslund, 2016/06/01 04:28:17]

I'm all of keeping it.  Yay for opportunistic clean up!

   }
 }