Minor perf and size optimization - don't do asserts in release build

base/lazy_instance.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // The LazyInstance<Type, Traits> class manages a single instance of Type,
 // which will be lazily created on the first time it's accessed.  This class is
 // useful for places you would normally use a function-level static, but you
 // need to have guaranteed thread-safety.  The Type constructor will only ever
 // be called once, even if two threads are racing to create the object.  Get()
 // and Pointer() will always return the same, completely initialized instance.
@@ skipping 115 matching lines @@
   // Declaring a destructor (even if it's empty) will cause MSVC to register a
   // static initializer to register the empty destructor with atexit().
   // Refer to the destructor-related comment in LazyInstanceHelper.
   // ~LazyInstance() {}
 
   Type& Get() {
     return *Pointer();
   }
 
   Type* Pointer() {
+#ifndef NDEBUG
+    // Avoid making TLS lookup on release builds.
     if (!Traits::kAllowedToAccessOnNonjoinableThread)
       base::ThreadRestrictions::AssertSingletonAllowed();
+#endif
 
     // We will hopefully have fast access when the instance is already created.
     // Since a thread sees state_ != STATE_CREATED at most once,
     // the load is taken out of NeedsInstance() as a fast-path.
     // The load has acquire memory ordering as a thread which sees
     // state_ == STATE_CREATED needs to acquire visibility over
     // the associated data (buf_). Pairing Release_Store is in
     // CompleteInstance().
     if ((base::subtle::Acquire_Load(&state_) != STATE_CREATED) &&
         NeedsInstance()) {
@@ skipping 38 matching lines @@
 
   Type *instance_;
   int8 buf_[sizeof(Type)];  // Preallocate the space for the Type instance.
 
   DISALLOW_COPY_AND_ASSIGN(LazyInstance);
 };
 
 }  // namespace base
 
 #endif  // BASE_LAZY_INSTANCE_H_