ui: Cache the output of View::OnPaint when the View isn't invalid.

ui/compositor/BUILD.gn

 # Copyright 2014 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("//build/config/ui.gni")
 import("//testing/test.gni")
 
 component("compositor") {
   sources = [
     "clip_transform_recorder.cc",
@@ skipping 29 matching lines @@
     "layer_animator.cc",
     "layer_animator.h",
     "layer_animator_collection.cc",
     "layer_animator_collection.h",
     "layer_delegate.h",
     "layer_owner.cc",
     "layer_owner.h",
     "layer_tree_owner.cc",
     "layer_tree_owner.h",
     "layer_type.h",
+    "paint_cache.cc",
+    "paint_cache.h",
     "paint_context.cc",
     "paint_context.h",
     "paint_recorder.cc",
     "paint_recorder.h",
     "reflector.cc",
     "reflector.h",
     "scoped_animation_duration_scale_mode.cc",
     "scoped_animation_duration_scale_mode.h",
     "scoped_layer_animation_settings.cc",
     "scoped_layer_animation_settings.h",
@@ skipping 118 matching lines @@
       "//ui/gfx/geometry",
       "//ui/gl",
       "//ui/resources",
     ]
 
     if (is_linux) {
       deps += [ "//third_party/mesa:osmesa" ]
     }
   }
 }