Turn the utility process image decoder into a Mojo service.

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 96000e029e632ff1945dc4e0c38e766d68c8906a..fbec8eb0a7053cfcc102186afc921809c0785dbd 100644
--- a/chrome/browser/image_decoder.h
+++ b/chrome/browser/image_decoder.h
@@ -17,6 +17,7 @@
 #include "base/timer/timer.h"
 #include "content/public/browser/utility_process_host.h"
 #include "content/public/browser/utility_process_host_client.h"
+#include "services/image_decoder/public/interfaces/image_decoder.mojom.h"
 
 class SkBitmap;
 
@@ -125,6 +126,9 @@ class ImageDecoder : public content::UtilityProcessHostClient {
   void OnDecodeImageSucceeded(const SkBitmap& decoded_image, int request_id);
   void OnDecodeImageFailed(int request_id);
 
+  // Mojo IPC callback.
+  void OnDecodeImageDone(int request_id, skia::BitmapPtr image);
+
   // Removes the job from the map of requests.
   void RemoveJob(const scoped_refptr<Job>& job);
 
@@ -146,6 +150,10 @@ class ImageDecoder : public content::UtilityProcessHostClient {
   // The time Start was last called.
   base::TimeTicks last_request_;
 
+  // Mojo service connection. Must always be bound/reset and used on the IO
+  // thread.
+  services::ImageDecoderPtr decoder_;
+
   DISALLOW_COPY_AND_ASSIGN(ImageDecoder);
 };