Add option to gen_snapshot for creating a Makefile describing a snapshot's dependencies.

runtime/bin/file.h

 // Copyright (c) 2013, 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_FILE_H_
 #define RUNTIME_BIN_FILE_H_
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ skipping 104 matching lines @@
   int64_t Write(const void* buffer, int64_t num_bytes);
 
   // ReadFully and WriteFully do attempt to transfer num_bytes to/from
   // the buffer. In the event of short accesses they will loop internally until
   // the whole buffer has been transferred or an error occurs. If an error
   // occurred the result will be set to false.
   bool ReadFully(void* buffer, int64_t num_bytes);
   bool WriteFully(const void* buffer, int64_t num_bytes);
   bool WriteByte(uint8_t byte) { return WriteFully(&byte, 1); }
 
+  bool Print(const char* format, ...) PRINTF_ATTRIBUTE(2, 3) {
+    va_list args;
+    va_start(args, format);
+    bool result = VPrint(format, args);
+    va_end(args);
+    return result;
+  }
+  bool VPrint(const char* format, va_list args);
+
   // Get the length of the file. Returns a negative value if the length cannot
   // be determined (e.g. not seekable device).
   int64_t Length();
 
   // Get the current position in the file.
   // Returns a negative value if position cannot be determined.
   int64_t Position();
 
   // Set the byte position in the file.
   bool SetPosition(int64_t position);
@@ skipping 123 matching lines @@
   Dart_WeakPersistentHandle weak_handle_;
 
   friend class ReferenceCounted<File>;
   DISALLOW_COPY_AND_ASSIGN(File);
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // RUNTIME_BIN_FILE_H_