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 854 matching lines @@
   device_input_format_ = media::VideoFrame::UNKNOWN;
   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);
+  int input_planes_count = media::VideoFrame::NumPlanes(input_format);

[xhwang, 2014/05/15 00:51:45]

What problem is this causing? converting from int to size_t should be valid...

[yunlian, 2014/05/15 16:34:13]

The problem is in the DCHECK_LE in the following line. I use static_cast for
VIDEO_MAX_PLANES now.

   DCHECK_LE(input_planes_count, 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;
@@ skipping 201 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