Fix analyzer's SDK detection so that during integration tests, we use the built SDK.

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

Index: pkg/analyzer/lib/src/dart/sdk/sdk.dart
diff --git a/pkg/analyzer/lib/src/dart/sdk/sdk.dart b/pkg/analyzer/lib/src/dart/sdk/sdk.dart
index 303e6a49f917532b809816a197506a967fce831c..fc1a2d3c7493611163430792533bcf21a3701515 100644
--- a/pkg/analyzer/lib/src/dart/sdk/sdk.dart
+++ b/pkg/analyzer/lib/src/dart/sdk/sdk.dart
@@ -698,7 +698,16 @@ class FolderBasedDartSdk extends AbstractDartSdk {
     String outDir = pathContext.dirname(pathContext.dirname(exec));
     String sdkPath = pathContext.join(pathContext.dirname(outDir), "sdk");
     if (resourceProvider.getFolder(sdkPath).exists) {
-      return sdkPath;
+      // We are executing in the context of a test.  sdkPath is the path to the
+      // *source* files for the SDK.  But we want to test using the path to the
+      // *built* SDK if possible.
+      String builtSdkPath =
+          pathContext.join(pathContext.dirname(exec), 'dart-sdk');
+      if (resourceProvider.getFolder(sdkPath).exists) {

[zra, 2016/12/12 19:16:17]

Shouldn't this be checking the existence of buildSdkPath rather than sdkPath?
This is probably what is causing the build failure.

[Paul Berry, 2016/12/12 19:24:39]

Yes, I just noticed this as well.  Thanks.

[Paul Berry, 2016/12/12 19:27:50]

Fix is here: https://codereview.chromium.org/2568253002/

+        return builtSdkPath;
+      } else {
+        return sdkPath;
+      }
     }
     // probably be "dart-sdk/bin/dart"
     return pathContext.dirname(pathContext.dirname(exec));