IWYU: ffloor(3) needs <cmath>.

cc/output/color_lut_cache.cc

 // Copyright 2016 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.
 
 #include "cc/output/color_lut_cache.h"
 
 #include <stdint.h>
+#include <cmath>
 #include <vector>
 
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "ui/gfx/color_transform.h"
 
 // After a LUT has not been used for this many frames, we release it.
 const uint32_t kMaxFramesUnused = 10;
 
 ColorLUTCache::ColorLUTCache(gpu::gles2::GLES2Interface* gl)
     : lut_cache_(0), gl_(gl) {}
@@ skipping 81 matching lines @@
 
 void ColorLUTCache::Swap() {
   current_frame_++;
   while (!lut_cache_.empty() &&
          current_frame_ - lut_cache_.rbegin()->second.first >
              kMaxFramesUnused) {
     gl_->DeleteTextures(1, &lut_cache_.rbegin()->second.first);
     lut_cache_.ShrinkToSize(lut_cache_.size() - 1);
   }
 }