Move spin_lock into partition_allocator.

base/allocator/partition_allocator/spin_lock.h

Index: base/allocator/partition_allocator/spin_lock.h
diff --git a/base/synchronization/spin_lock.h b/base/allocator/partition_allocator/spin_lock.h
similarity index 89%
rename from base/synchronization/spin_lock.h
rename to base/allocator/partition_allocator/spin_lock.h
index cf44414de49d4158c0b6d7e215f6cde448aed241..300a5dfdcb2ae8a646ad4982bae7ed4efda8ca33 100644
--- a/base/synchronization/spin_lock.h
+++ b/base/allocator/partition_allocator/spin_lock.h
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef BASE_SYNCHRONIZATION_SPIN_LOCK_H
-#define BASE_SYNCHRONIZATION_SPIN_LOCK_H
+#ifndef BASE_ALLOCATOR_PARTITION_ALLOCATOR_SPIN_LOCK_H
+#define BASE_ALLOCATOR_PARTITION_ALLOCATOR_SPIN_LOCK_H
 
 #include <atomic>
 #include <memory>
@@ -49,4 +49,4 @@ class SpinLock {
 }  // namespace subtle
 }  // namespace base
 
-#endif  // BASE_SYNCHRONIZATION_SPIN_LOCK_H
+#endif  // BASE_ALLOCATOR_PARTITION_ALLOCATOR_SPIN_LOCK_H