Don't use LazyInstance in chrome/browser/image_decoder.*

chrome/browser/image_decoder.h

Index: chrome/browser/image_decoder.h
diff --git a/chrome/browser/image_decoder.h b/chrome/browser/image_decoder.h
index d8bda97454fab4f214441aa5624a14423f0b330e..2770662f3657eee796a61fa2407fd2592130fd2f 100644
--- a/chrome/browser/image_decoder.h
+++ b/chrome/browser/image_decoder.h
@@ -71,8 +71,7 @@ class ImageDecoder {
 #endif  // defined(OS_CHROMEOS)
   };
 
-  ImageDecoder();
-  ~ImageDecoder();
+  static ImageDecoder* GetInstance();
 
   // Calls StartWithOptions() with ImageCodec::DEFAULT_CODEC and
   // shrink_to_fit = false.
@@ -101,6 +100,9 @@ class ImageDecoder {
  private:
   using RequestMap = std::map<int, ImageRequest*>;
 
+  ImageDecoder();
+  ~ImageDecoder() = delete;
+
   void StartWithOptionsImpl(ImageRequest* image_request,
                             std::vector<uint8_t> image_data,
                             ImageCodec image_codec,