Initial isolate reload support

runtime/vm/unit_test.h

Index: runtime/vm/unit_test.h
diff --git a/runtime/vm/unit_test.h b/runtime/vm/unit_test.h
index a8224c58c15bb4c51492513d343ef2a1572715d7..ac7645a8ec9ae9754d7c88658e27c59edb85ac90 100644
--- a/runtime/vm/unit_test.h
+++ b/runtime/vm/unit_test.h
@@ -286,7 +286,6 @@ class TestCase : TestCaseBase {
                                     Dart_NativeEntryResolver resolver,
                                     const char* lib_uri = USER_TEST_URI,
                                     bool finalize = true);
-
   static Dart_Handle LoadCoreTestScript(const char* script,
                                         Dart_NativeEntryResolver resolver);
   static Dart_Handle lib();
@@ -305,6 +304,16 @@ class TestCase : TestCaseBase {
 
   virtual void Run();
 
+  // Sets |script| to be the source used at next reload.
+  static void SetReloadTestScript(const char* script);
+  // Initiates the reload.
+  static Dart_Handle TriggerReload();
+  // Gets the result of a reload.
+  static Dart_Handle GetReloadErrorOrRootLibrary();
+
+  // Helper function which reloads the current isolate using |script|.
+  static Dart_Handle ReloadTestScript(const char* script);
+
  private:
   static Dart_Isolate CreateIsolate(const uint8_t* buffer, const char* name);
 
@@ -586,6 +595,24 @@ class CompilerTest : public AllStatic {
 void ElideJSONSubstring(const char* prefix, const char* in, char* out);
 
 
+template<typename T>
+class SetFlagScope : public ValueObject {
+ public:
+  SetFlagScope(T* flag, T value)
+      : flag_(flag),
+        original_value_(*flag) {
+    *flag_ = value;
+  }
+
+  ~SetFlagScope() {
+    *flag_ = original_value_;
+  }
+
+ private:
+  T* flag_;
+  T original_value_;
+};
+
 }  // namespace dart
 
 #endif  // VM_UNIT_TEST_H_