update code completion suggestion relevance based on common usage

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 21307d553142c03936547e54218b3fbc7fff7d4f..fa5428cb151f1bba5720edf4cf6aad1ace8f3478 100644
--- a/pkg/analysis_server/test/domain_completion_test.dart
+++ b/pkg/analysis_server/test/domain_completion_test.dart
@@ -484,6 +484,60 @@ class CompletionTest extends AbstractAnalysisTest {
     });
   }
 
+  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() {