Move ImageProcessor destructor to .cc file

After https://crrev.com/c/1937958 was landed, on some build
configurations ImageProcessor became large enough for chromium style
checked to forbid inline destructor.

This commit moves destructor to image_processor.cc file, after that this
is no more issue for style checker.

Change-Id: I36efb3601fc9305ef61af1705618e6156528489a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1941313
Commit-Queue: Oleg Davydov <burunduk@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Auto-Submit: Oleg Davydov <burunduk@chromium.org>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719943}

media/gpu/chromeos/image_processor.cc

@@ -102,6 +102,8 @@ ImageProcessor::ImageProcessor(
   DETACH_FROM_SEQUENCE(client_sequence_checker_);
 }
 
+ImageProcessor::~ImageProcessor() = default;
+
 #if defined(OS_POSIX) || defined(OS_FUCHSIA)
 bool ImageProcessor::Process(scoped_refptr<VideoFrame> frame,
                              LegacyFrameReadyCB cb) {

media/gpu/chromeos/image_processor.h

@@ -94,7 +94,7 @@ class MEDIA_GPU_EXPORT ImageProcessor {
   // be executed on |client_task_runner_|.
   using ErrorCB = base::RepeatingClosure;
 
-  virtual ~ImageProcessor() = default;
+  virtual ~ImageProcessor();
 
   const PortConfig& input_config() const { return input_config_; }
   const PortConfig& output_config() const { return output_config_; }