Semantic highlight async/await/sync/yield.

pkg/analysis_server/lib/src/computer/computer_highlights.dart

Index: pkg/analysis_server/lib/src/computer/computer_highlights.dart
diff --git a/pkg/analysis_server/lib/src/computer/computer_highlights.dart b/pkg/analysis_server/lib/src/computer/computer_highlights.dart
index 7e9eed87be263ea65888e4d243b3a6f6f3941928..50c51711b0860038aa8af4238c2ab715f56238fe 100644
--- a/pkg/analysis_server/lib/src/computer/computer_highlights.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_highlights.dart
@@ -371,6 +371,18 @@ class _DartUnitHighlightsComputerVisitor extends RecursiveAstVisitor<Object> {
   }
 
   @override
+  Object visitAwaitExpression(AwaitExpression node) {
+    computer._addRegion_token(node.awaitKeyword, HighlightRegionType.BUILT_IN);
+    return super.visitAwaitExpression(node);
+  }
+
+  @override
+  Object visitBlockFunctionBody(BlockFunctionBody node) {
+    _addRegions_functionBody(node);
+    return super.visitBlockFunctionBody(node);
+  }
+
+  @override
   Object visitBooleanLiteral(BooleanLiteral node) {
     computer._addRegion_node(node, HighlightRegionType.KEYWORD);
     computer._addRegion_node(node, HighlightRegionType.LITERAL_BOOLEAN);
@@ -451,6 +463,12 @@ class _DartUnitHighlightsComputerVisitor extends RecursiveAstVisitor<Object> {
   }
 
   @override
+  Object visitExpressionFunctionBody(ExpressionFunctionBody node) {
+    _addRegions_functionBody(node);
+    return super.visitExpressionFunctionBody(node);
+  }
+
+  @override
   Object visitFieldDeclaration(FieldDeclaration node) {
     computer._addRegion_token(node.staticKeyword, HighlightRegionType.BUILT_IN);
     return super.visitFieldDeclaration(node);
@@ -694,4 +712,24 @@ class _DartUnitHighlightsComputerVisitor extends RecursiveAstVisitor<Object> {
     computer._addRegion_token(node.withKeyword, HighlightRegionType.KEYWORD);
     return super.visitWithClause(node);
   }
+
+  @override
+  Object visitYieldStatement(YieldStatement node) {
+    Token keyword = node.yieldKeyword;
+    Token star = node.star;
+    int offset = keyword.offset;
+    int end = star != null ? star.end : keyword.end;
+    computer._addRegion(offset, end - offset, HighlightRegionType.BUILT_IN);
+    return super.visitYieldStatement(node);
+  }
+
+  void _addRegions_functionBody(FunctionBody node) {
+    Token keyword = node.keyword;
+    if (keyword != null) {
+      Token star = node.star;
+      int offset = keyword.offset;
+      int end = star != null ? star.end : keyword.end;
+      computer._addRegion(offset, end - offset, HighlightRegionType.BUILT_IN);
+    }
+  }
 }