Trigger analysis when context.applyChanges request is received.

pkg/analysis_server/test/domain_context_test.dart

Index: pkg/analysis_server/test/domain_context_test.dart
diff --git a/pkg/analysis_server/test/domain_context_test.dart b/pkg/analysis_server/test/domain_context_test.dart
index 358aea07bb02fa41fa300b678b9a44a519e27b3e..2181565ff7216d509f0d316f4da0636329425c42 100644
--- a/pkg/analysis_server/test/domain_context_test.dart
+++ b/pkg/analysis_server/test/domain_context_test.dart
@@ -42,7 +42,9 @@ class ContextDomainHandlerTest {
       ContextDomainHandler.MODIFIED_PARAM : ['ffile:/two.dart'],
       ContextDomainHandler.REMOVED_PARAM : ['ffile:/three.dart']
     });
+    expect(server.contextWorkQueue, isEmpty);
     Response response = handler.handleRequest(request);
+    expect(server.contextWorkQueue, hasLength(1));
     expect(response.toJson(), equals({
       Response.ID: '0',
       Response.ERROR: null