Initial implementation of ServiceWorkerCache.

net/base/io_buffer.h

Index: net/base/io_buffer.h
diff --git a/net/base/io_buffer.h b/net/base/io_buffer.h
index 0ce52e8d79c02473adabd6af98e2e9272d9b2fdb..421fa23faea48333ab3a594e707ca38ad1b34ec7 100644
--- a/net/base/io_buffer.h
+++ b/net/base/io_buffer.h
@@ -123,6 +123,24 @@ class NET_EXPORT StringIOBuffer : public IOBuffer {
   std::string string_data_;
 };
 
+// This versions allows a string to be used as the storage for a write-style
+// operation, avoiding an extra data copy.
+class NET_EXPORT ZeroCopyStringIOBuffer : public IOBuffer {
+ public:
+  ZeroCopyStringIOBuffer();
+
+  std::string* string() { return &string_; }
+
+  // Signals that we are done writing to the string and we can use it for a
+  // write-style IO operation.
+  void Done();
+
+ private:
+  virtual ~ZeroCopyStringIOBuffer();
+
+  std::string string_;
+};
+
 // This version wraps an existing IOBuffer and provides convenient functions
 // to progressively read all the data.
 //