Merge changes I0dcc9c7b,I9bc40642

* changes:
  Move cc.imageMutator into the android package
  Make CreateVariations return []android.Module

Android.bp

@@ -51,6 +51,7 @@ bootstrap_go_package {
         "android/expand.go",
         "android/filegroup.go",
         "android/hooks.go",
+        "android/image.go",
         "android/makevars.go",
         "android/module.go",
         "android/mutator.go",