Modify extension request IPC messages to pass a ListValue instead of a string.

base/values.h

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file specifies a recursive data storage class called Value
 // intended for storing setting and other persistable data.
 // It includes the ability to specify (recursive) lists and dictionaries, so
 // it's fairly expressive.  However, the API is optimized for the common case,
 // namely storing a hierarchical tree of simple values.  Given a
 // DictionaryValue root, you can easily do things like:
@@ skipping 153 matching lines @@
  public:
   // Creates a Value to represent a binary buffer.  The new object takes
   // ownership of the pointer passed in, if successful.
   // Returns NULL if buffer is NULL.
   static BinaryValue* Create(char* buffer, size_t size);
 
   // For situations where you want to keep ownership of your buffer, this
   // factory method creates a new BinaryValue by copying the contents of the
   // buffer that's passed in.
   // Returns NULL if buffer is NULL.
-  static BinaryValue* CreateWithCopiedBuffer(char* buffer, size_t size);
+  static BinaryValue* CreateWithCopiedBuffer(const char* buffer, size_t size);
 
   ~BinaryValue();
 
   // Subclassed methods
   Value* DeepCopy() const;
   virtual bool Equals(const Value* other) const;
 
   size_t GetSize() const { return size_; }
   char* GetBuffer() { return buffer_; }
+  const char* GetBuffer() const { return buffer_; }
 
  private:
   // Constructor is private so that only objects with valid buffer pointers
   // and size values can be created.
   BinaryValue(char* buffer, size_t size);
 
   char* buffer_;
   size_t size_;
 
   DISALLOW_COPY_AND_ASSIGN(BinaryValue);
@@ skipping 177 matching lines @@
   virtual bool Serialize(const Value& root) = 0;
 
   // This method deserializes the subclass-specific format into a Value object.
   // If the return value is non-NULL, the caller takes ownership of returned
   // Value. If the return value is NULL, and if error_message is non-NULL,
   // error_message should be filled with a message describing the error.
   virtual Value* Deserialize(std::string* error_message) = 0;
 };
 
 #endif  // BASE_VALUES_H_