Add _embedder.yaml support to analyzer and analysis_server

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 feb1f789bf7b33a5aef62633e8e0dc2a23a00f0f..b5e67e10e6b9c325c81571051f2e3a1a3ceb4040 100644
--- a/pkg/analyzer/lib/src/context/context.dart
+++ b/pkg/analyzer/lib/src/context/context.dart
@@ -9,6 +9,7 @@ import 'dart:collection';
 
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/plugin/task.dart';
+import 'package:analyzer/source/embedder.dart';
 import 'package:analyzer/src/cancelable_future.dart';
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ -81,6 +82,9 @@ class AnalysisContextImpl implements InternalAnalysisContext {
    */
   AnalysisOptionsImpl _options = new AnalysisOptionsImpl();
 
+  /// The embedder yaml locator for this context.
+  EmbedderYamlLocator _embedderYamlLocator = new EmbedderYamlLocator(null);
+
   /**
    * A flag indicating whether this context is disposed.
    */
@@ -252,6 +256,9 @@ class AnalysisContextImpl implements InternalAnalysisContext {
   AnalysisOptions get analysisOptions => _options;
 
   @override
+  EmbedderYamlLocator get embedderYamlLocator => _embedderYamlLocator;
+
+  @override
   void set analysisOptions(AnalysisOptions options) {
     bool needsRecompute = this._options.analyzeFunctionBodiesPredicate !=
             options.analyzeFunctionBodiesPredicate ||