Introduce IKG into kernel-service to support incremental compilation.

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 e023ae9e8ac53a4f2aad7a8ac49266f5d23f7234..6c70bb967b375728afd5b0267bf400e81b21a16a 100644
--- a/runtime/vm/unit_test.h
+++ b/runtime/vm/unit_test.h
@@ -286,11 +286,23 @@ class TestCase : TestCaseBase {
 
   static char* CompileTestScriptWithDFE(const char* url,
                                         const char* source,
-                                        void** kernel_pgm);
+                                        void** kernel_pgm,
+                                        bool incrementally = false);
+  static char* CompileTestScriptWithDFE(const char* url,
+                                        int sourcefiles_count,
+                                        Dart_SourceFile sourcefiles[],
+                                        void** kernel_pgm,
+                                        bool incrementally = false);
   static Dart_Handle LoadTestScript(const char* script,
                                     Dart_NativeEntryResolver resolver,
                                     const char* lib_uri = USER_TEST_URI,
                                     bool finalize = true);
+  static Dart_Handle LoadTestScriptWithDFE(
+      int sourcefiles_count,
+      Dart_SourceFile sourcefiles[],
+      Dart_NativeEntryResolver resolver = NULL,
+      bool finalize = true,
+      bool incrementally = false);
   static Dart_Handle LoadCoreTestScript(const char* script,
                                         Dart_NativeEntryResolver resolver);
   static Dart_Handle lib();
@@ -311,6 +323,8 @@ class TestCase : TestCaseBase {
 
   // Sets |script| to be the source used at next reload.
   static void SetReloadTestScript(const char* script);
+  static void SetReloadTestKernel(const void* kernel);
+
   // Initiates the reload.
   static Dart_Handle TriggerReload();
   // Gets the result of a reload.
@@ -318,6 +332,7 @@ class TestCase : TestCaseBase {
 
   // Helper function which reloads the current isolate using |script|.
   static Dart_Handle ReloadTestScript(const char* script);
+  static Dart_Handle ReloadTestKernel(const void* kernel);
 
   static void AddTestLib(const char* url, const char* source);
   static const char* GetTestLib(const char* url);