Update from https://crrev.com/304418

cc/debug/ring_buffer.h

 // Copyright 2013 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.
 
 #ifndef CC_DEBUG_RING_BUFFER_H_
 #define CC_DEBUG_RING_BUFFER_H_
 
 #include "base/logging.h"
 
 namespace cc {
 
 template<typename T, size_t kSize>
 class RingBuffer {
  public:
-  explicit RingBuffer()
-    : current_index_(0) {
-  }
+  RingBuffer() : current_index_(0) {}
 
   size_t BufferSize() const {
     return kSize;
   }
 
   size_t CurrentIndex() const {
     return current_index_;
   }
 
   // tests if a value was saved to this index
@@ skipping 85 matching lines @@
 
   T buffer_[kSize];
   size_t current_index_;
 
   DISALLOW_COPY_AND_ASSIGN(RingBuffer);
 };
 
 }  // namespace cc
 
 #endif  // CC_DEBUG_RING_BUFFER_H_