deals solely with a weak FileHandle.
CrashReportDatabase::PrepareNewCrashReport() provides its caller with
both a FileHandle and a FilePath. While it’s possible to create a
FileWriter from the FilePath, it’s not necessary to have two FileHandles
open to the same file. Also, there’s no FileWriteMode::kReuseOrFail
option because it didn’t seem necessary[1], and although it would
actually be the most desirable option for a FileWriter here, allowing
the FileHandle to be used directly without reopening the file sidesteps
the problem entirely.
FileWriter is adapted to use WeakFileHandleFileWriter to minimize
duplication.
[1] https://codereview.chromium.org/818433002/diff/80001/util/file/file_io.h#newcode138R=rsesek@chromium.org, scottmg@chromium.org
Review URL: https://codereview.chromium.org/871193010