extract LibraryMemberContributor from prefixed element contributor

pkg/analysis_server/test/domain_completion_test.dart

Index: pkg/analysis_server/test/domain_completion_test.dart
diff --git a/pkg/analysis_server/test/domain_completion_test.dart b/pkg/analysis_server/test/domain_completion_test.dart
index 888b7ccf911ace21c6ed41cd88ad38f2b3b14f31..184ebef9cbfe58437ef759b8ac329532a9574e19 100644
--- a/pkg/analysis_server/test/domain_completion_test.dart
+++ b/pkg/analysis_server/test/domain_completion_test.dart
@@ -470,6 +470,19 @@ class CompletionTest extends AbstractAnalysisTest {
     });
   }
 
+  test_imports_prefixed2() {
+    addTestFile('''
+      import 'dart:html' as foo;
+      main() {foo.^}
+    ''');
+    return getSuggestions().then((_) {
+      expect(replacementOffset, equals(completionOffset));
+      expect(replacementLength, equals(0));
+      assertHasResult(CompletionSuggestionKind.INVOCATION, 'HtmlElement');
+      assertNoResult('test');
+    });
+  }
+
   test_invocation() {
     addTestFile('class A {b() {}} main() {A a; a.^}');
     return getSuggestions().then((_) {
@@ -632,6 +645,16 @@ class B extends A {m() {^}}
     });
   }
 
+  test_static() {
+    addTestFile('class A {static b() {} c() {}} main() {A.^}');
+    return getSuggestions().then((_) {
+      expect(replacementOffset, equals(completionOffset));
+      expect(replacementLength, equals(0));
+      assertHasResult(CompletionSuggestionKind.INVOCATION, 'b');
+      assertNoResult('c');
+    });
+  }
+
   test_topLevel() {
     addTestFile('''
       typedef foo();