Prioritize analysis of files that import the changed file, or have an error or warning.

pkg/analyzer/lib/src/dart/analysis/driver.dart

Index: pkg/analyzer/lib/src/dart/analysis/driver.dart
diff --git a/pkg/analyzer/lib/src/dart/analysis/driver.dart b/pkg/analyzer/lib/src/dart/analysis/driver.dart
index 871be4cfb0407f41a110328e54ddabf2f5db7c85..a501db5653923f60ab66b0985ffdf509aae17759 100644
--- a/pkg/analyzer/lib/src/dart/analysis/driver.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/driver.dart
@@ -1086,6 +1086,7 @@ class AnalysisDriver implements AnalysisDriverGeneric {
       {String content, CompilationUnit resolvedUnit}) {
     var unit = new AnalysisDriverResolvedUnit.fromBuffer(bytes);
     List<AnalysisError> errors = _getErrorsFromSerialized(file, unit.errors);
+    _updateHasErrorOrWarningFlag(file, errors);
     return new AnalysisResult(
         this,
         _sourceFactory,
@@ -1242,6 +1243,23 @@ class AnalysisDriver implements AnalysisDriverGeneric {
       return null;
     }
   }
+
+  /**
+   * Given the list of [errors] for the [file], update the [file]'s
+   * [FileState.hasErrorOrWarning] flag.
+   */
+  void _updateHasErrorOrWarningFlag(
+      FileState file, List<AnalysisError> errors) {
+    for (AnalysisError error in errors) {
+      ErrorSeverity severity = error.errorCode.errorSeverity;
+      if (severity == ErrorSeverity.ERROR ||
+          severity == ErrorSeverity.WARNING) {
+        file.hasErrorOrWarning = true;
+        return;
+      }
+    }
+    file.hasErrorOrWarning = false;
+  }
 }
 
 /**