Roll src/third_party/leveldatabase/src/ 7b945f200..73d5834ec (3 commits)

https://chromium.googlesource.com/external/leveldb.git/+log/7b945f200339..73d5834eceee

This CL also removes port_chromium's InitOnce implementation, because it
is no longer used by leveldb.

$ git log 7b945f200..73d5834ec --date=short --no-merges --format='%ad %ae %s'
2018-09-11 costan Rework threading in env_posix.cc.
2018-09-10 costan Remove InitOnce from the port API.
2018-09-05 costan Clean up PosixWritableFile in env_posix.cc.

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

Change-Id: Icba857ff32949a1b6f4cd385330a01c7ac02798d
Reviewed-on: https://chromium-review.googlesource.com/c/1220056Reviewed-by: Chris Mumford <cmumford@chromium.org>
Commit-Queue: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596422}

DEPS

@@ -804,7 +804,7 @@ deps = {
   },
 
   'src/third_party/leveldatabase/src':
-    Var('chromium_git') + '/external/leveldb.git' + '@' + '7b945f200339aa47c24788d3ee9910c09c513843',
+    Var('chromium_git') + '/external/leveldb.git' + '@' + '73d5834eceee8efa9a8ccfec77dc096a9e8ba18a',
 
   'src/third_party/libFuzzer/src':
     Var('chromium_git') + '/chromium/llvm-project/compiler-rt/lib/fuzzer.git' + '@' +  Var('libfuzzer_revision'),

third_party/leveldatabase/port/port_chromium.cc

@@ -48,27 +48,6 @@ void CondVar::SignalAll() {
   cv_.Broadcast();
 }
 
-void InitOnceImpl(OnceType* once, void (*initializer)()) {
-  OnceType state = base::subtle::Acquire_Load(once);
-  if (state == ONCE_STATE_DONE)
-    return;
-
-  state = base::subtle::NoBarrier_CompareAndSwap(once, ONCE_STATE_UNINITIALIZED,
-                                                 ONCE_STATE_EXECUTING_CLOSURE);
-
-  if (state == ONCE_STATE_UNINITIALIZED) {
-    // We are the first thread, we have to call the closure.
-    (*initializer)();
-    base::subtle::Release_Store(once, ONCE_STATE_DONE);
-  } else {
-    // Another thread is running the closure, wait until completion.
-    while (state == ONCE_STATE_EXECUTING_CLOSURE) {
-      base::PlatformThread::YieldCurrentThread();
-      state = base::subtle::Acquire_Load(once);
-    }
-  }
-}
-
 bool Snappy_Compress(const char* input,
                      size_t input_length,
                      std::string* output) {

third_party/leveldatabase/port/port_chromium.h

@@ -85,26 +85,6 @@ class AtomicPointer {
   Rep rep_;
 };
 
-// Implementation of OnceType and InitOnce() pair, this is equivalent to
-// pthread_once_t and pthread_once().
-typedef base::subtle::Atomic32 OnceType;
-
-enum {
-  ONCE_STATE_UNINITIALIZED = 0,
-  ONCE_STATE_EXECUTING_CLOSURE = 1,
-  ONCE_STATE_DONE = 2
-};
-
-#define LEVELDB_ONCE_INIT   leveldb::port::ONCE_STATE_UNINITIALIZED
-
-// slow code path
-void InitOnceImpl(OnceType* once, void (*initializer)());
-
-static inline void InitOnce(OnceType* once, void (*initializer)()) {
-  if (base::subtle::Acquire_Load(once) != ONCE_STATE_DONE)
-    InitOnceImpl(once, initializer);
-}
-
 bool Snappy_Compress(const char* input, size_t input_length,
                      std::string* output);
 bool Snappy_GetUncompressedLength(const char* input, size_t length,