Provide LINE_INFO using just UnlinkedUnit even though the full info is not available.

pkg/analyzer/lib/src/context/context.dart

Index: pkg/analyzer/lib/src/context/context.dart
diff --git a/pkg/analyzer/lib/src/context/context.dart b/pkg/analyzer/lib/src/context/context.dart
index d0a2104ba50a2596685d47b97f6497fd01448a8d..a255836fa0d6bf53378d91a3796bcdd8af7d081d 100644
--- a/pkg/analyzer/lib/src/context/context.dart
+++ b/pkg/analyzer/lib/src/context/context.dart
@@ -720,6 +720,12 @@ class AnalysisContextImpl implements InternalAnalysisContext {
     CacheEntry entry = getCacheEntry(target);
     CacheState state = entry.getState(descriptor);
     if (state == CacheState.FLUSHED || state == CacheState.INVALID) {
+      // Check the result provider.
+      bool success = aboutToComputeResult(entry, descriptor);
+      if (success) {
+        return entry.getValue(descriptor);
+      }
+      // Compute the result.
       driver.computeResult(target, descriptor);
       entry = getCacheEntry(target);
     }