clang/win: Make dump_file_system.cc build.

clang/win: Make dump_file_system.cc build.

In clang/win/gn builds, this file warned:
../../storage/browser/fileapi/dump_file_system.cc(96,71) : error: invalid suffix on literal; C++11 requires a space between literal and identifier [-Werror,-Wreserved-user-defined-literal]
      ShowMessageAndExit(base::StringPrintf("GetFileInfo failed for %"PRId64,
                                                                      ^

In gyp builds, nothing in build/all.gyp depends on this target, and in non-Win
gn src/BUILD.gn blacklists this target.  So this warning is only seen on
clang/win gn builds.

No behavior change.

BUG=491209
TBR=tzik

Committed: https://chromium.googlesource.com/chromium/src/+/10531819b506d7e8b6b6415f5da8882885f4d779

[Nico, 2015-09-01 23:23:33]

thakis@chromium.org changed reviewers:
+ tzik@chromium.org

[Nico, 2015-09-01 23:27:29]

Committed patchset #1 (id:1) manually as
10531819b506d7e8b6b6415f5da8882885f4d779 (presubmit successful).

[tzik, 2015-09-02 05:31:43]

lgtm