Add support for reading blobs when using the network service.

storage/browser/blob/blob_url_request_job.h

Index: storage/browser/blob/blob_url_request_job.h
diff --git a/storage/browser/blob/blob_url_request_job.h b/storage/browser/blob/blob_url_request_job.h
index 4d83d60322d0c3dd7880dbb646f261f8d34b7dd4..3eb264c52c9a43c5e17036d9ab8b71a8d5912a31 100644
--- a/storage/browser/blob/blob_url_request_job.h
+++ b/storage/browser/blob/blob_url_request_job.h
@@ -24,6 +24,7 @@ class SingleThreadTaskRunner;
 }
 
 namespace net {
+class HttpResponseHeaders;
 class IOBuffer;
 }
 
@@ -51,6 +52,19 @@ class STORAGE_EXPORT BlobURLRequestJob
   void GetResponseInfo(net::HttpResponseInfo* info) override;
   void SetExtraRequestHeaders(const net::HttpRequestHeaders& headers) override;
 
+  // Helper method to create the HTTP headers for the response.
+  // |blob_handles|, |blob_reader|, |byte_range| and |content_size| are only
+  // used if status_code isn't an error.
+  static scoped_refptr<net::HttpResponseHeaders> GenerateHeaders(
+      net::HttpStatusCode status_code,
+      BlobDataHandle* blob_handle,
+      BlobReader* blob_reader,
+      net::HttpByteRange* byte_range,
+      int64_t* content_size);
+
+  // Helper method to map from a net error to an http status code.
+  static net::HttpStatusCode NetErrorToHttpStatusCode(int error_code);
+
  protected:
   ~BlobURLRequestJob() override;