Fix the case where the browser livelocks if we cannot open a file.

net/base/upload_data.cc

Index: net/base/upload_data.cc
diff --git a/net/base/upload_data.cc b/net/base/upload_data.cc
index 0045409bf5479318de97b12ae20da9f18f86d4b7..87b6426e6e47db81242f3074bd62f9f50813fee4 100644
--- a/net/base/upload_data.cc
+++ b/net/base/upload_data.cc
@@ -23,11 +23,12 @@ uint64 UploadData::Element::GetContentLength() const {
 
   DCHECK(type_ == TYPE_FILE);
 
-  // TODO(darin): This size calculation could be out of sync with the state of
-  // the file when we get around to reading it.  We should probably find a way
-  // to lock the file or somehow protect against this error condition.
+  expected_file_length_ = 0;
 
-  int64 length = 0;
+  if (!file_util::PathIsReadable(file_path_))

[darin (slow to review), 2010/01/12 07:57:45]

on windows, it might be nice to combine these two calls since you can get the
file size from an open file handle.

[agl, 2010/01/25 14:14:09]

PathIsReadable no longer obtains a file handle, so there's nothing to merge now.

+    return 0;
+
+  int64 length;
   if (!file_util::GetFileSize(file_path_, &length))
     return 0;
 
@@ -35,7 +36,9 @@ uint64 UploadData::Element::GetContentLength() const {
     return 0;  // range is beyond eof
 
   // compensate for the offset and clip file_range_length_ to eof
-  return std::min(length - file_range_offset_, file_range_length_);
+  expected_file_length_ = std::min(length - file_range_offset_,
+                                   file_range_length_);
+  return expected_file_length_;
 }
 
 }  // namespace net