Add a priority to source changes for assists and fixes

pkg/analyzer_plugin/test/integration/support/protocol_matchers.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
 /**
  * Matchers for data types defined in the analysis server API
@@ skipping 313 matching lines @@
   "edit.getAssists params", {
     "file": isFilePath,
     "offset": isInt,
     "length": isInt
   }));
 
 /**
  * edit.getAssists result
  *
  * {
- *   "assists": List<SourceChange>
+ *   "assists": List<PrioritizedSourceChange>
  * }
  */
 final Matcher isEditGetAssistsResult = new LazyMatcher(() => new MatchesJsonObject(
   "edit.getAssists result", {
-    "assists": isListOf(isSourceChange)
+    "assists": isListOf(isPrioritizedSourceChange)
   }));
 
 /**
  * edit.getAvailableRefactorings params
  *
  * {
  *   "file": FilePath
  *   "offset": int
  *   "length": int
  * }
@@ skipping 126 matching lines @@
   }, optionalFields: {
     "correction": isString,
     "hasFix": isBool
   }));
 
 /**
  * AnalysisErrorFixes
  *
  * {
  *   "error": AnalysisError
- *   "fixes": List<SourceChange>
+ *   "fixes": List<PrioritizedSourceChange>
  * }
  */
 final Matcher isAnalysisErrorFixes = new LazyMatcher(() => new MatchesJsonObject(
   "AnalysisErrorFixes", {
     "error": isAnalysisError,
-    "fixes": isListOf(isSourceChange)
+    "fixes": isListOf(isPrioritizedSourceChange)
   }));
 
 /**
  * AnalysisErrorSeverity
  *
  * enum {
  *   INFO
  *   WARNING
  *   ERROR
  * }
@@ skipping 607 matching lines @@
  *   "offset": int
  * }
  */
 final Matcher isPosition = new LazyMatcher(() => new MatchesJsonObject(
   "Position", {
     "file": isFilePath,
     "offset": isInt
   }));
 
 /**
+ * PrioritizedSourceChange
+ *
+ * {
+ *   "priority": int
+ *   "change": SourceChange
+ * }
+ */
+final Matcher isPrioritizedSourceChange = new LazyMatcher(() => new MatchesJsonObject(
+  "PrioritizedSourceChange", {
+    "priority": isInt,
+    "change": isSourceChange
+  }));
+
+/**
  * RefactoringFeedback
  *
  * {
  * }
  */
 final Matcher isRefactoringFeedback = new LazyMatcher(() => new MatchesJsonObject(
   "RefactoringFeedback", null));
 
 /**
  * RefactoringKind
@@ skipping 421 matching lines @@
  *
  * {
  *   "newName": String
  * }
  */
 final Matcher isRenameOptions = new LazyMatcher(() => new MatchesJsonObject(
   "rename options", {
     "newName": isString
   }));