[BlobStorage] Implementing disk.

storage/browser/blob/blob_reader.cc

Index: storage/browser/blob/blob_reader.cc
diff --git a/storage/browser/blob/blob_reader.cc b/storage/browser/blob/blob_reader.cc
index 1ec3002a8d103b34cc77ddc1f3f1ee150de82bf6..42356839eada765f59982dc2d6614c6db2de0789 100644
--- a/storage/browser/blob/blob_reader.cc
+++ b/storage/browser/blob/blob_reader.cc
@@ -14,6 +14,7 @@
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
+#include "base/debug/stack_trace.h"
 #include "base/sequenced_task_runner.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
@@ -245,6 +246,8 @@ bool BlobReader::IsInMemory() const {
 
 void BlobReader::InvalidateCallbacksAndDone(int net_error,
                                             net::CompletionCallback done) {
+  LOG(ERROR) << "Async error: " << net_error
+             << " with stack: " << base::debug::StackTrace().ToString();
   net_error_ = net_error;
   weak_factory_.InvalidateWeakPtrs();
   size_callback_.Reset();
@@ -254,6 +257,8 @@ void BlobReader::InvalidateCallbacksAndDone(int net_error,
 }
 
 BlobReader::Status BlobReader::ReportError(int net_error) {
+  LOG(ERROR) << "Error: " << net_error
+             << " with stack: " << base::debug::StackTrace().ToString();
   net_error_ = net_error;
   return Status::NET_ERROR;
 }
@@ -373,6 +378,9 @@ void BlobReader::DidGetFileItemLength(size_t index, int64_t result) {
   if (net_error_)
     return;
 
+  if (result < 0)
+    LOG(ERROR) << "Got file error " << result;
+
   if (result == net::ERR_UPLOAD_FILE_CHANGED)
     result = net::ERR_FILE_NOT_FOUND;
   if (result < 0) {