[Suggestions] Create ImageEncoder, to abstract away image encode/decode.

components/suggestions.gypi

Index: components/suggestions.gypi
diff --git a/components/suggestions.gypi b/components/suggestions.gypi
index e03dc2199ea2793e1b3b1261008dd9ca751f624c..88c71353ca5f6e53cfa7bace4547960b0dbc9ec4 100644
--- a/components/suggestions.gypi
+++ b/components/suggestions.gypi
@@ -24,6 +24,7 @@
       'sources': [
         'suggestions/blacklist_store.cc',
         'suggestions/blacklist_store.h',
+        'suggestions/image_encoder.h',
         'suggestions/image_fetcher.h',
         'suggestions/image_fetcher_delegate.h',
         'suggestions/image_manager.cc',
@@ -44,5 +45,22 @@
       },
       'includes': [ '../build/protoc.gypi' ],
     },
-  ],
+    # TODO(justincohen): iOS cannot depend on ui/gfx, so we should provide an
+    # implementation of the image encoder, and put this target in a block that
+    # excludes iOS.
+    {
+      # GN version: //components/suggestions:jpeg_image_encoder
+      'target_name': 'jpeg_image_encoder',
+      'type': 'static_library',
+      'dependencies': [
+        '../base/base.gyp:base',
+        '../ui/gfx/gfx.gyp:gfx',
+        'suggestions',
+      ],
+      'sources': [
+        'suggestions/jpeg/jpeg_image_encoder.cc',
+        'suggestions/jpeg/jpeg_image_encoder.h',
+      ],
+    }
+  ]
 }