update code completion suggestion relevance based on common usage

pkg/analysis_server/test/domain_completion_test.dart

 // Copyright (c) 2014, 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.
 
 library test.domain.completion;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/channel/channel.dart';
@@ skipping 466 matching lines @@
     return getSuggestions().then((_) {
       expect(replacementOffset, equals(completionOffset));
       expect(replacementLength, equals(0));
       assertHasResult(CompletionSuggestionKind.INVOCATION, 'Object');
       assertHasResult(CompletionSuggestionKind.INVOCATION, 'HtmlElement');
       assertHasResult(CompletionSuggestionKind.INVOCATION, 'A');
       assertNoResult('test');
     });
   }
 
+  test_relevance_ConstructorName() {
+    // SimpleIdentifier  ConstructorName  InstanceCreationExpression
+    addTestFile('import "dart:async"; class A {x() {new Future.^}}');
+    return getSuggestions().then((_) {
+      expect(replacementOffset, equals(completionOffset));
+      expect(replacementLength, equals(0));
+      assertHasResult(CompletionSuggestionKind.INVOCATION, 'delayed');
+      assertHasResult(
+          CompletionSuggestionKind.INVOCATION,
+          'value',
+          DART_RELEVANCE_COMMON_USAGE);
+      assertNoResult('Future');
+      assertNoResult('Object');
+      assertNoResult('A');
+    });
+  }
+
+  test_relevance_PrefixedIdentifier() {
+    // SimpleIdentifier  PrefixedIdentifeir  ExpressionStatement
+    addTestFile('import "dart:async"; class A {x() {Future.^}}');
+    return getSuggestions().then((_) {
+      expect(replacementOffset, equals(completionOffset));
+      expect(replacementLength, equals(0));
+      assertHasResult(
+          CompletionSuggestionKind.INVOCATION,
+          'wait',
+          DART_RELEVANCE_COMMON_USAGE - 1);
+      assertNoResult('Future');
+      assertNoResult('Object');
+      assertNoResult('A');
+    });
+  }
+
+  test_relevance_PropertyAccess() {
+    // SimpleIdentifier  PropertyAccess  ExpressionStatement
+    addTestFile('import "dart:math"; class A {x() {new Random().^}}');
+    return getSuggestions().then((_) {
+      expect(replacementOffset, equals(completionOffset));
+      expect(replacementLength, equals(0));
+      assertHasResult(CompletionSuggestionKind.INVOCATION, 'nextBool');
+      assertHasResult(
+          CompletionSuggestionKind.INVOCATION,
+          'nextDouble',
+          DART_RELEVANCE_COMMON_USAGE - 1);
+      assertHasResult(
+          CompletionSuggestionKind.INVOCATION,
+          'nextInt',
+          DART_RELEVANCE_COMMON_USAGE);
+      assertNoResult('Random');
+      assertNoResult('Object');
+      assertNoResult('A');
+    });
+  }
+
   test_simple() {
     addTestFile('''
       void main() {
         ^
       }
     ''');
     return getSuggestions().then((_) {
       expect(replacementOffset, equals(completionOffset));
       expect(replacementLength, equals(0));
       assertHasResult(CompletionSuggestionKind.INVOCATION, 'Object');
@@ skipping 161 matching lines @@
 
   void contextsChangedRaw(ContextsChangedEvent newEvent) {
     super.contextsChanged(newEvent);
   }
 
   CompletionManager createCompletionManager(AnalysisContext context,
       Source source, SearchEngine searchEngine) {
     return new MockCompletionManager(mockContext, source, searchEngine);
   }
 }