Turn the utility process image decoder into a Mojo service.

skia/skia.gyp

Index: skia/skia.gyp
diff --git a/skia/skia.gyp b/skia/skia.gyp
index 109adffdbed91a98f2aad5a60c976debbacaff39..a538f3e6cd78b280568e38be3b52e78a0c3f4db6 100644
--- a/skia/skia.gyp
+++ b/skia/skia.gyp
@@ -146,5 +146,22 @@
         '../build/android/increase_size_for_speed.gypi',
       ],
     },
+    {
+      'target_name': 'skia_mojo',
+      'type': 'static_library',
+      'dependencies': [
+        'skia',
+        '../base/base.gyp:base',
+      ],
+      'includes': [
+        '../third_party/mojo/mojom_bindings_generator.gypi',
+      ],
+      'sources': [
+        # Note: file list duplicated in GN build.
+        'public/interfaces/bitmap.mojom',
+        'public/type_converters.cc',
+        'public/type_converters.h',
+      ],
+    },
   ],
 }