Add 'Add != null' quick fix.

pkg/analysis_server/lib/src/services/correction/fix_internal.dart

Index: pkg/analysis_server/lib/src/services/correction/fix_internal.dart
diff --git a/pkg/analysis_server/lib/src/services/correction/fix_internal.dart b/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
index ba774a99ffbf17a48cb12eedc0edd43435943896..52e82a291cab54fac5a4d52859915a3f65b71bf9 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix_internal.dart
@@ -271,6 +271,9 @@ class FixProcessor {
     if (errorCode == StaticTypeWarningCode.INVOCATION_OF_NON_FUNCTION) {
       _addFix_removeParentheses_inGetterInvocation();
     }
+    if (errorCode == StaticTypeWarningCode.NON_BOOL_CONDITION) {
+      _addFix_nonBoolCondition_addNotNull();
+    }
     if (errorCode == StaticTypeWarningCode.NON_TYPE_AS_TYPE_ARGUMENT) {
       _addFix_importLibrary_withType();
       _addFix_createClass();
@@ -1518,6 +1521,11 @@ class FixProcessor {
     _addFix(DartFixKind.MAKE_CLASS_ABSTRACT, [className]);
   }
 
+  void _addFix_nonBoolCondition_addNotNull() {
+    _addInsertEdit(error.offset + error.length, ' != null');
+    _addFix(DartFixKind.ADD_NE_NULL, []);
+  }
+
   void _addFix_removeDeadCode() {
     AstNode coveringNode = this.coveredNode;
     if (coveringNode is Expression) {