Add buffering to MimeSniffingResourceHandler.

content/browser/loader/redirect_to_file_resource_handler_unittest.cc

Index: content/browser/loader/redirect_to_file_resource_handler_unittest.cc
diff --git a/content/browser/loader/redirect_to_file_resource_handler_unittest.cc b/content/browser/loader/redirect_to_file_resource_handler_unittest.cc
index 666bc67ac870002326acbd75d00d5fa3b03a460d..38ff6634f66269583d5fb872d5ca1ebef7a11f02 100644
--- a/content/browser/loader/redirect_to_file_resource_handler_unittest.cc
+++ b/content/browser/loader/redirect_to_file_resource_handler_unittest.cc
@@ -31,7 +31,6 @@
 #include "net/base/completion_callback.h"
 #include "net/base/file_stream.h"
 #include "net/base/io_buffer.h"
-#include "net/base/mime_sniffer.h"
 #include "net/base/net_errors.h"
 #include "net/base/request_priority.h"
 #include "net/url_request/url_request.h"
@@ -46,11 +45,9 @@ namespace content {
 namespace {
 
 // The maximum size for which the initial read will always be sync, even when
-// the wrote completes asynchronously.  See
-// RedirectToFileResourceHandler::BufIsFull().
+// the write completes asynchronously.
 const int kMaxInitialSyncReadSize =
-    RedirectToFileResourceHandler::kInitialReadBufSize -
-    2 * net::kMaxBytesToSniff - 1;
+    RedirectToFileResourceHandler::kInitialReadBufSize - 1;
 
 // Used to indicate whether FileStream operations and the lower-layer
 // TestResourceHandler operations should complete immediately or by