move extractDefinedVariables from analyzer cli to analyzer

pkg/analyzer/test/src/command_line/arguments_test.dart

Index: pkg/analyzer/test/src/command_line/arguments_test.dart
diff --git a/pkg/analyzer/test/src/command_line/arguments_test.dart b/pkg/analyzer/test/src/command_line/arguments_test.dart
index 17aff4141290ea36e0257e48d505ff3b557137f3..8ed6dba80d1818ffaf10b0cc627a4b76e5f164bf 100644
--- a/pkg/analyzer/test/src/command_line/arguments_test.dart
+++ b/pkg/analyzer/test/src/command_line/arguments_test.dart
@@ -142,6 +142,18 @@ class ArgumentsTest {
     expect(parser.options, hasLength(12));
   }
 
+  void test_extractDefinedVariables() {
+    List<String> args = ['--a', '-Dbaz', 'go', 'back=blue', '-Dx'];
+    Map<String, String> definedVariables = {'one': 'two'};
+    args = extractDefinedVariables(args, definedVariables);
+    expect(args, orderedEquals(['--a', 'back=blue', '-Dx']));
+    expect(definedVariables['one'], 'two');
+    expect(definedVariables['two'], isNull);
+    expect(definedVariables['baz'], 'go');
+    expect(definedVariables['go'], isNull);
+    expect(definedVariables, hasLength(2));
+  }
+
   void test_filterUnknownArguments() {
     List<String> args = ['--a', '--b', '--c', 'foo', 'bar'];
     ArgParser parser = new ArgParser();