Migrate from CRITICAL_SECTION to SRWLOCK

base/synchronization/lock_impl_win.cc

Index: base/synchronization/lock_impl_win.cc
diff --git a/base/synchronization/lock_impl_win.cc b/base/synchronization/lock_impl_win.cc
index fbc1bdd464b01254fb4bef8a9e2f1053553d3a07..d89a131a7a8a8fb84950baaaf572334e36fa85b8 100644
--- a/base/synchronization/lock_impl_win.cc
+++ b/base/synchronization/lock_impl_win.cc
@@ -7,29 +7,20 @@
 namespace base {
 namespace internal {
 
-LockImpl::LockImpl() {
-  // The second parameter is the spin count, for short-held locks it avoid the
-  // contending thread from going to sleep which helps performance greatly.
-  ::InitializeCriticalSectionAndSpinCount(&native_handle_, 2000);
-}
+LockImpl::LockImpl() : native_handle_(SRWLOCK_INIT) {}
 
-LockImpl::~LockImpl() {
-  ::DeleteCriticalSection(&native_handle_);
-}
+LockImpl::~LockImpl() = default;
 
 bool LockImpl::Try() {
-  if (::TryEnterCriticalSection(&native_handle_) != FALSE) {
-    return true;
-  }
-  return false;
+  return !!::TryAcquireSRWLockExclusive(&native_handle_);
 }
 
 void LockImpl::Lock() {
-  ::EnterCriticalSection(&native_handle_);
+  ::AcquireSRWLockExclusive(&native_handle_);

[scottmg, 2016/04/06 22:36:12]

SRWs aren't recursive where CSs are, right? Is this going to magically be OK?

[robliao, 2016/04/06 22:51:09]

Yup, because we don't permit recursive Locks.
See
https://code.google.com/p/chromium/codesearch#chromium/src/base/synchronizati...

 }
 
 void LockImpl::Unlock() {
-  ::LeaveCriticalSection(&native_handle_);
+  ::ReleaseSRWLockExclusive(&native_handle_);
 }
 
 }  // namespace internal