Added a debug method AssertAcquired() that compiles to nothing in non-debug b...

base/lock_impl_win.cc

Index: base/lock_impl_win.cc
===================================================================
--- base/lock_impl_win.cc	(revision 11968)
+++ base/lock_impl_win.cc	(working copy)
@@ -13,6 +13,7 @@
 #ifndef NDEBUG
   recursion_count_shadow_ = 0;
   recursion_used_ = false;
+  owning_thread_id_ = 0;
 #endif  // NDEBUG
   // The second parameter is the spin count, for short-held locks it avoid the
   // contending thread from going to sleep which helps performance greatly.
@@ -26,6 +27,9 @@
 bool LockImpl::Try() {
   if (::TryEnterCriticalSection(&os_lock_) != FALSE) {
 #ifndef NDEBUG
+    // ONLY access data after locking.
+    owning_thread_id_ = PlatformThread::CurrentId();
+    DCHECK_NE(owning_thread_id_, 0);
     recursion_count_shadow_++;
     if (2 == recursion_count_shadow_ && !recursion_used_) {
       recursion_used_ = true;
@@ -41,6 +45,8 @@
   ::EnterCriticalSection(&os_lock_);
 #ifndef NDEBUG
   // ONLY access data after locking.
+  owning_thread_id_ = PlatformThread::CurrentId();
+  DCHECK_NE(owning_thread_id_, 0);
   recursion_count_shadow_++;
   if (2 == recursion_count_shadow_ && !recursion_used_) {
     recursion_used_ = true;
@@ -53,6 +59,15 @@
 #ifndef NDEBUG
   --recursion_count_shadow_;  // ONLY access while lock is still held.
   DCHECK(0 <= recursion_count_shadow_);
+  owning_thread_id_ = 0;
 #endif  // NDEBUG
   ::LeaveCriticalSection(&os_lock_);
 }
+
+// In non-debug builds, this method is declared as an empty inline method.
+#ifndef NDEBUG
+void LockImpl::AssertAcquired() {
+  DCHECK(recursion_count_shadow_ > 0);
+  DCHECK_EQ(owning_thread_id_, PlatformThread::CurrentId());
+}
+#endif