Added member data to classes to support download resumption.

content/browser/download/base_file.h

Index: content/browser/download/base_file.h
diff --git a/content/browser/download/base_file.h b/content/browser/download/base_file.h
index 2a0994358055c89d9f84c59b1fca13c4f5076f5e..493099630bbd7e32aa130e46132ccde32a6cea47 100644
--- a/content/browser/download/base_file.h
+++ b/content/browser/download/base_file.h
@@ -33,6 +33,7 @@ class CONTENT_EXPORT BaseFile {
            const GURL& source_url,
            const GURL& referrer_url,
            int64 received_bytes,
+           const std::string& hash_state,
            const linked_ptr<net::FileStream>& file_stream);
   virtual ~BaseFile();
 
@@ -65,10 +66,16 @@ class CONTENT_EXPORT BaseFile {
   bool in_progress() const { return file_stream_ != NULL; }
   int64 bytes_so_far() const { return bytes_so_far_; }
 
-  // Set |hash| with sha256 digest for the file.
+  // Fills |hash| with the sha256 digest for the file.
   // Returns true if digest is successfully calculated.
   virtual bool GetSha256Hash(std::string* hash);
 
+  // Returns the current (intermediate) state of the hash as a byte string.
+  virtual std::string GetSha256HashState();
+
+  // Resets the current state of the hash to the contents of |hash_state_bytes|.
+  virtual bool SetSha256HashState(const std::string& hash_state_bytes);
+
   // Returns true if the given hash is considered empty.  An empty hash is
   // a string of size kSha256HashLen that contains only zeros (initial value
   // for the hash).
@@ -114,6 +121,9 @@ class CONTENT_EXPORT BaseFile {
   // is set.
   scoped_ptr<crypto::SecureHash> secure_hash_;
 
+  // The hash state is stored here on creation.
+  std::string initial_hash_state_;
+
   unsigned char sha256_hash_[kSha256HashLen];
 
   // Indicates that this class no longer owns the associated file, and so