fix sign-compare warning.

content/common/gpu/media/video_encode_accelerator_unittest.cc

 // 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.
 
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 515 matching lines @@
     // Without it, AppendToFile() will not work.
     EXPECT_EQ(0, base::WriteFile(out_filename, NULL, 0));
   }
 
   input_buffer_size_ =
       media::VideoFrame::AllocationSize(kInputFormat, test_stream.size);
   CHECK_GT(input_buffer_size_, 0UL);
 
   // Calculate the number of frames in the input stream by dividing its length
   // in bytes by frame size in bytes.
-  CHECK_EQ(test_stream_.input_file.length() % input_buffer_size_, 0)
+  CHECK_EQ(test_stream_.input_file.length() % input_buffer_size_, 0U)
       << "Stream byte size is not a product of calculated frame byte size";
   num_frames_in_stream_ = test_stream_.input_file.length() / input_buffer_size_;
   CHECK_GT(num_frames_in_stream_, 0UL);
   CHECK_LE(num_frames_in_stream_, kMaxFrameNum);
 
   // We may need to loop over the stream more than once if more frames than
   // provided is required for bitrate tests.
   if (force_bitrate_ && num_frames_in_stream_ < kMinFramesForBitrateTests) {
     DVLOG(1) << "Stream too short for bitrate test (" << num_frames_in_stream_
              << " frames), will loop it to reach " << kMinFramesForBitrateTests
@@ skipping 471 matching lines @@
       test_stream_data->assign(it->second.c_str());
       continue;
     }
     if (it->first == "v" || it->first == "vmodule")
       continue;
     LOG(FATAL) << "Unexpected switch: " << it->first << ":" << it->second;
   }
 
   return RUN_ALL_TESTS();
 }