Schetch changes required to support URLFetcher saving response to a file

chrome/common/net/url_fetcher.h

Index: chrome/common/net/url_fetcher.h
diff --git a/chrome/common/net/url_fetcher.h b/chrome/common/net/url_fetcher.h
index 3ed0e6491c1fdf81394df470874f585927d8ebca..bf2648ca4c6a9c6c1aff76b7c901fe89ef718922 100644
--- a/chrome/common/net/url_fetcher.h
+++ b/chrome/common/net/url_fetcher.h
@@ -67,12 +67,36 @@ class URLFetcher {
     HEAD,
   };
 
+  // Abstract class used to hold the response body. Delegate generates
+  // an implementation of this interface, and gets a pointer to it when
+  // the fetch is complete.
+  class ResponseBodyContainerInterface {
+   public:
+    // Add bytes to the response body.
+    virtual void Append(char* data, int data_length) = 0;
+
+    // If the class supports returning the body as a string, return true
+    // and set |out_body| to the response body. Otherwise, return false.
+    virtual bool GetAsString(std::string* out_body) const = 0;
+  };
+
   class Delegate {
    public:
     // This will be called when the URL has been fetched, successfully or not.
     // |response_code| is the HTTP response code (200, 404, etc.) if
     // applicable.  |url|, |status| and |data| are all valid until the
     // URLFetcher instance is destroyed.
+    virtual void OnURLFetchCompleteNew(
+        const URLFetcher* source,
+        const GURL& url,
+        const net::URLRequestStatus& status,
+        int response_code,
+        const ResponseCookies& cookies,
+        const ResponseBodyContainerInterface& response_body);
+
+    // TODO(skerner): To avoid changing existing code, keep the old
+    // method, whre |data| is a string.  Once we finalize interface changes,
+    // this will be removed.
     virtual void OnURLFetchComplete(const URLFetcher* source,
                                     const GURL& url,
                                     const net::URLRequestStatus& status,
@@ -80,6 +104,13 @@ class URLFetcher {
                                     const ResponseCookies& cookies,
                                     const std::string& data) = 0;
 
+    // Get a container into which the response body can be written.
+    // Delegate can control how response is held by the choice of the
+    // concrete type this method returns. For example, to process the
+    // response body as it is received, return a class that does
+    // processing on each call to ResponseBodyContainerInterface::Append().
+    virtual ResponseBodyContainerInterface* CreateResponseBodyContainer();
+
    protected:
     virtual ~Delegate() {}
   };