VM: Support bootstrapping core libraries from Kernel binaries instead of source.

runtime/vm/bootstrap.h

Index: runtime/vm/bootstrap.h
diff --git a/runtime/vm/bootstrap.h b/runtime/vm/bootstrap.h
index 0c2d9124adbdac930e158c52933f77a041bdf492..77fb556f450fb264c6b8a7b0c01a8abc31e123f1 100644
--- a/runtime/vm/bootstrap.h
+++ b/runtime/vm/bootstrap.h
@@ -15,7 +15,15 @@ class RawError;
 
 class Bootstrap : public AllStatic {
  public:
-  static RawError* DoBootstrapping();
+  // Compile the bootstrap libraries, either from sources or a Kernel binary.
+  // If kernel_buffer is NULL, compile from sources or source paths linked into
+  // the VM.  If it is non-NULL it represents a buffer holding a Kernel binary.
+  // The caller of this function is responsible for managing the kernel
+  // buffer's memory, and is welcome to deallocate it after this function
+  // returns.
+  static RawError* DoBootstrapping(const uint8_t* kernel_buffer,
+                                   intptr_t kernel_buffer_length);
+
   static void SetupNativeResolver();
   static bool IsBootstapResolver(Dart_NativeEntryResolver resolver);