suggest keywords in if expression

pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart

Index: pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart b/pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart
index 699a5cd6ed47ca95af97a957aa45e4da8fd24081..99c9ce31bd3fbde43a4d5736b9917fb5f9a31ca3 100644
--- a/pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/keyword_contributor.dart
@@ -191,6 +191,8 @@ class _KeywordVisitor extends GeneralizingAstVisitor {
   visitIfStatement(IfStatement node) {
     if (entity == node.thenStatement) {
       _addStatementKeywords(node);
+    } else if (entity == node.condition) {
+      _addExpressionKeywords(node);
     }
   }