Restructure the Kernel string table.

runtime/vm/kernel.h

 // Copyright (c) 2016, 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_VM_KERNEL_H_
 #define RUNTIME_VM_KERNEL_H_
 
 #if !defined(DART_PRECOMPILED_RUNTIME)
 #include "platform/assert.h"
 #include "vm/allocation.h"
@@ skipping 239 matching lines @@
 
   Ref<A> first_;
   Child<B> second_;
 
   DISALLOW_COPY_AND_ASSIGN(Tuple);
 };
 
 
 class String {
  public:
+  // Read a string reference, which is an index into the string table.
   static String* ReadFrom(Reader* reader);
+
+  // Read a string implementation, which is a size followed by a UTF-8
+  // encoded string.
   static String* ReadFromImpl(Reader* reader);
 
+  // Read a string implementation given its size.
+  static String* ReadRaw(Reader* reader, intptr_t size);
+
   String(const uint8_t* utf8, int length) {
     buffer_ = new uint8_t[length];
     size_ = length;
     memmove(buffer_, utf8, length);
   }
   ~String() { delete[] buffer_; }
 
   uint8_t* buffer() { return buffer_; }
   int size() { return size_; }
 
@@ skipping 2878 matching lines @@
 
 kernel::Program* ReadPrecompiledKernelFromBuffer(const uint8_t* buffer,
                                                  intptr_t buffer_length);
 
 
 
 }  // namespace dart
 
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)
 #endif  // RUNTIME_VM_KERNEL_H_