Move ImageSerializationProcessor code to blimp/client/core

blimp/test/BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//testing/test.gni")
 
 source_set("run_all_unittests") {
   testonly = true
 
   sources = [
     "run_all_unittests.cc",
   ]
 
   deps = [
     "//base/test:test_support",
     "//mojo/edk/system",
   ]
 }
 
 source_set("support") {
   testonly = true
 
   sources = [
     "support/compositor/picture_cache_test_support.cc",
     "support/compositor/picture_cache_test_support.h",
   ]
 
   deps = [
+    "//ui/gfx",
+    "//ui/gfx/geometry",
+  ]
+
+  public_deps = [
     "//blimp/common",
     "//cc",
     "//skia",
     "//testing/gmock",
-    "//ui/gfx",
-    "//ui/gfx/geometry",
   ]
 }