Provide an API to dart:developer to control the web server hosting the Service Protocol

runtime/observatory/tests/service/test_helper.dart

Index: runtime/observatory/tests/service/test_helper.dart
diff --git a/runtime/observatory/tests/service/test_helper.dart b/runtime/observatory/tests/service/test_helper.dart
index 63b8fc2bb97231c11cc4683971353398e2bed074..43ae11d00494ba9fab0159d21162469c96350dbe 100644
--- a/runtime/observatory/tests/service/test_helper.dart
+++ b/runtime/observatory/tests/service/test_helper.dart
@@ -91,25 +91,29 @@ class _ServiceTesteeLauncher {
                                 bool pause_on_exit,
                                 bool pause_on_unhandled_exceptions,
                                 bool trace_service,
-                                bool trace_compiler) {
+                                bool trace_compiler,
+                                bool testeeControlsServer) {
     assert(pause_on_start != null);
     assert(pause_on_exit != null);
     assert(pause_on_unhandled_exceptions != null);
     assert(trace_service != null);
     assert(trace_compiler != null);
+    assert(testeeControlsServer != null);
 
     if (_shouldLaunchSkyShell()) {
       return _spawnSkyProcess(pause_on_start,
                               pause_on_exit,
                               pause_on_unhandled_exceptions,
                               trace_service,
-                              trace_compiler);
+                              trace_compiler,
+                              testeeControlsServer);
     } else {
       return _spawnDartProcess(pause_on_start,
                                pause_on_exit,
                                pause_on_unhandled_exceptions,
                                trace_service,
-                               trace_compiler);
+                               trace_compiler,
+                               testeeControlsServer);
     }
   }
 
@@ -117,7 +121,8 @@ class _ServiceTesteeLauncher {
                                     bool pause_on_exit,
                                     bool pause_on_unhandled_exceptions,
                                     bool trace_service,
-                                    bool trace_compiler) {
+                                    bool trace_compiler,
+                                    bool testeeControlsServer) {
     assert(!_shouldLaunchSkyShell());
 
     String dartExecutable = Platform.executable;
@@ -141,7 +146,9 @@ class _ServiceTesteeLauncher {
     }
 
     fullArgs.addAll(Platform.executableArguments);
-    fullArgs.add('--enable-vm-service:0');
+    if (!testeeControlsServer) {
+      fullArgs.add('--enable-vm-service:0');
+    }
     fullArgs.addAll(args);
 
     return _spawnCommon(dartExecutable, fullArgs);
@@ -179,7 +186,9 @@ class _ServiceTesteeLauncher {
     dartFlags.add('--enable_mirrors=true');
 
     fullArgs.addAll(Platform.executableArguments);
-    fullArgs.add('--observatory-port=0');
+    if (!testeeControlsServer) {
+      fullArgs.add('--observatory-port=0');
+    }
     fullArgs.add('--dart-flags=${dartFlags.join(' ')}');
     fullArgs.addAll(args);
 
@@ -198,12 +207,14 @@ class _ServiceTesteeLauncher {
                      bool pause_on_exit,
                      bool pause_on_unhandled_exceptions,
                      bool trace_service,
-                     bool trace_compiler) {
+                     bool trace_compiler,
+                     bool testeeControlsServer) {
     return _spawnProcess(pause_on_start,
                   pause_on_exit,
                   pause_on_unhandled_exceptions,
                   trace_service,
-                  trace_compiler).then((p) {
+                  trace_compiler,
+                  testeeControlsServer).then((p) {
       Completer completer = new Completer();
       process = p;
       var portNumber;
@@ -317,11 +328,13 @@ class _ServiceTesterRunner {
             bool trace_service: false,
             bool trace_compiler: false,
             bool verbose_vm: false,
-            bool pause_on_unhandled_exceptions: false}) {
+            bool pause_on_unhandled_exceptions: false,
+            bool testeeControlsServer: false}) {
     var process = new _ServiceTesteeLauncher();
     process.launch(pause_on_start, pause_on_exit,
                    pause_on_unhandled_exceptions,
-                   trace_service, trace_compiler).then((port) async {
+                   trace_service, trace_compiler,
+                   testeeControlsServer).then((port) async {
       if (mainArgs.contains("--gdb")) {
         var pid = process.process.pid;
         var wait = new Duration(seconds: 10);
@@ -386,7 +399,8 @@ Future runIsolateTests(List<String> mainArgs,
                         bool trace_service: false,
                         bool trace_compiler: false,
                         bool verbose_vm: false,
-                        bool pause_on_unhandled_exceptions: false}) async {
+                        bool pause_on_unhandled_exceptions: false,
+                        bool testeeControlsServer: false}) async {
   assert(!pause_on_start || testeeBefore == null);
   if (_isTestee()) {
     new _ServiceTesteeRunner().run(testeeBefore: testeeBefore,
@@ -402,7 +416,8 @@ Future runIsolateTests(List<String> mainArgs,
         trace_service: trace_service,
         trace_compiler: trace_compiler,
         verbose_vm: verbose_vm,
-        pause_on_unhandled_exceptions: pause_on_unhandled_exceptions);
+        pause_on_unhandled_exceptions: pause_on_unhandled_exceptions,
+        testeeControlsServer: testeeControlsServer);
   }
 }