Roll src/third_party/leveldatabase/src/ 4bd052d7e..53e280b56 (24 commits)

https://chromium.googlesource.com/external/leveldb.git/+log/4bd052d7e8b0..53e280b56866

$ git log 4bd052d7e..53e280b56 --date=short --no-merges --format='%ad %ae %s'
2019-06-13 cmumford Simplify unlocking in DeleteObsoleteFiles.
2019-06-12 cmumford Add "leveldb" subdirectory to public include paths.
2019-06-12 cmumford Ending sentences with periods in README.md.
2019-06-12 costan Align EnvPosix and EnvWindows.
2019-06-12 costan Disable exceptions and RTTI in CMake configuration.
2019-05-28 costan Replace "> >" with ">>"
2019-05-28 costan unsigned char -> uint8_t
2019-05-24 costan Use GCC 9 on Travis CI
2019-05-22 cmumford Add explicit typecasts to avoid compiler warning.
2019-05-15 cmumford Guard DBImpl::versions_ by mutex_.
2019-05-13 cmumford Converted two for-loops to while-loops.
2019-05-09 cmumford Switch to using C++ 11 override specifier.
2019-05-09 cmumford Added unit test for InternalKey::DecodeFrom with empty string.
2019-05-08 cmumford Using std::ostringstream in key DebugString.
2019-05-07 costan Fix EnvPosix tests on Travis CI.
2019-05-06 cmumford Formatting changes for prior O_CLOEXEC fix.
2019-05-06 costan Clean up util/coding.{h,cc}.
2019-05-06 cmumford Initialize Stats::start_ before first use in Stats::Start().
2016-04-08 allangj1618 Add argument definition for void c functions.
2018-09-19 adam.azarchs Add O_CLOEXEC to open calls.
2017-03-10 18814092650 fix comment
2016-10-03 proller broken db: fix assertion in leveldb::InternalKey::Encode, mark base as corrupt
2016-06-21 sjingivan set const property
2016-06-20 sjingivan reduce lock's range in DeleteObsoleteFiles

Created with:
  roll-dep src/third_party/leveldatabase/src

Change-Id: Id15df59ee9c3acbf9430ef959e6d90fd7e48d1fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1700161
Auto-Submit: Victor Costan <pwnall@chromium.org>
Reviewed-by: Chris Mumford <cmumford@google.com>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#677106}

DEPS

@@ -1036,7 +1036,7 @@ deps = {
   },
 
   'src/third_party/leveldatabase/src':
-    Var('chromium_git') + '/external/leveldb.git' + '@' + '4bd052d7e8b0469b2b87664388e2a99cb212ecdb',
+    Var('chromium_git') + '/external/leveldb.git' + '@' + '53e280b56866ac4c90a9f5fcfe02ebdfd4a19832',
 
   'src/third_party/libFuzzer/src':
     Var('chromium_git') + '/chromium/llvm-project/compiler-rt/lib/fuzzer.git' + '@' +  Var('libfuzzer_revision'),