Changes to make isolate reload functionality work with the --dfe option.

runtime/bin/dfe.h

Index: runtime/bin/dfe.h
diff --git a/runtime/bin/dfe.h b/runtime/bin/dfe.h
new file mode 100644
index 0000000000000000000000000000000000000000..b91568552f0132e7e429e669c65c437f2ee8ef8b
--- /dev/null
+++ b/runtime/bin/dfe.h
@@ -0,0 +1,58 @@
+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef RUNTIME_BIN_DFE_H_
+#define RUNTIME_BIN_DFE_H_
+
+#include "include/dart_api.h"
+#include "include/dart_native_api.h"
+#include "platform/assert.h"
+#include "platform/globals.h"
+
+namespace dart {
+namespace bin {
+
+class DFE {
+ public:
+  DFE();
+  ~DFE();
+
+  const char* frontend_filename() const { return frontend_filename_; }
+  void set_frontend_filename(const char* name) { frontend_filename_ = name; }
+  bool UseDartFrontend() const { return frontend_filename_ != NULL; }
+
+  const char* platform_binary_filename() const {
+    return platform_binary_filename_;
+  }
+  void set_platform_binary_filename(const char* name) {
+    platform_binary_filename_ = name;
+  }
+  bool UsePlatformBinary() const { return platform_binary_filename_ != NULL; }
+
+  // Method to reload a script into a running a isolate.
+  // If the specified script [url] is not a kernel IR, compile it first using
+  // DFE and then reload the resulting kernel IR into the isolate.
+  // Returns Dart_Null if successful, otherwise an error object is returned.
+  Dart_Handle ReloadScript(Dart_Isolate isolate, Dart_Handle url);
+
+  // Tries to read [script_uri] as a Kernel IR file.
+  // Returns `true` if successful and sets [kernel_file] and [kernel_length]
+  // to be the kernel IR contents.
+  // The caller is responsible for free()ing [kernel_file] if `true`
+  // was returned.
+  bool TryReadKernelFile(const char* script_uri,
+                         const uint8_t** kernel_ir,
+                         intptr_t* kernel_ir_size);
+
+ private:
+  const char* frontend_filename_;
+  const char* platform_binary_filename_;
+
+  DISALLOW_COPY_AND_ASSIGN(DFE);
+};
+
+}  // namespace bin
+}  // namespace dart
+
+#endif  // RUNTIME_BIN_DFE_H_