fix sign-compare warning.

content/common/gpu/media/v4l2_video_encode_accelerator.cc

 // Copyright 2014 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 <fcntl.h>
 #include <linux/videodev2.h>
 #include <poll.h>
 #include <sys/eventfd.h>
 #include <sys/ioctl.h>
 #include <sys/mman.h>
@@ skipping 855 matching lines @@
   input_planes_count_ = 0;
 
   uint32 input_format_fourcc =
       V4L2Device::VideoFrameFormatToV4L2PixFmt(input_format);
   if (!input_format_fourcc) {
     DVLOG(1) << "Unsupported input format";
     return false;
   }
 
   size_t input_planes_count = media::VideoFrame::NumPlanes(input_format);
-  DCHECK_LE(input_planes_count, VIDEO_MAX_PLANES);
+  DCHECK_LE(input_planes_count, static_cast<size_t>(VIDEO_MAX_PLANES));
 
   // First see if we the device can use the provided input_format directly.
   struct v4l2_format format;
   memset(&format, 0, sizeof(format));
   format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
   format.fmt.pix_mp.width = visible_size_.width();
   format.fmt.pix_mp.height = visible_size_.height();
   format.fmt.pix_mp.pixelformat = input_format_fourcc;
   format.fmt.pix_mp.num_planes = input_planes_count;
   if (device_->Ioctl(VIDIOC_S_FMT, &format) != 0) {
     // Error or format unsupported by device, try to negotiate a fallback.
     input_format_fourcc = device_->PreferredInputFormat();
     input_format =
         V4L2Device::V4L2PixFmtToVideoFrameFormat(input_format_fourcc);
     if (input_format == media::VideoFrame::UNKNOWN)
       return false;
 
     input_planes_count = media::VideoFrame::NumPlanes(input_format);
-    DCHECK_LE(input_planes_count, VIDEO_MAX_PLANES);
+    DCHECK_LE(input_planes_count, static_cast<size_t>(VIDEO_MAX_PLANES));
 
     // Device might have adjusted parameters, reset them along with the format.
     memset(&format, 0, sizeof(format));
     format.type = V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE;
     format.fmt.pix_mp.width = visible_size_.width();
     format.fmt.pix_mp.height = visible_size_.height();
     format.fmt.pix_mp.pixelformat = input_format_fourcc;
     format.fmt.pix_mp.num_planes = input_planes_count;
     IOCTL_OR_ERROR_RETURN_FALSE(VIDIOC_S_FMT, &format);
     DCHECK_EQ(format.fmt.pix_mp.num_planes, input_planes_count);
@@ skipping 181 matching lines @@
   reqbufs.count = 0;
   reqbufs.type = V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE;
   reqbufs.memory = V4L2_MEMORY_MMAP;
   IOCTL_OR_LOG_ERROR(VIDIOC_REQBUFS, &reqbufs);
 
   output_buffer_map_.clear();
   free_output_buffers_.clear();
 }
 
 }  // namespace content