add local caching for skia draws

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("//build_overrides/v8.gni")
 import("//testing/test.gni")
 import("pdfium.gni")
 
 config("pdfium_common_config") {
   cflags = []
@@ skipping 1472 matching lines @@
   include_dirs = []
   if (pdf_enable_xfa) {
     sources += [
       "xfa/fde/css/fde_cssdatatable_unittest.cpp",
       "xfa/fde/xml/fde_xml_imp_unittest.cpp",
       "xfa/fxbarcode/pdf417/BC_PDF417HighLevelEncoder_unittest.cpp",
       "xfa/fxfa/app/xfa_textlayout_unittest.cpp",
       "xfa/fxfa/parser/xfa_utils_imp_unittest.cpp",
     ]
   }
+  if (pdf_use_skia) {
+    sources += [ "core/fxge/skia/fx_skia_device_unittest.cpp" ]
+    deps += [ "//skia" ]
+  }
   if (pdf_enable_v8) {
     sources += [ "fpdfsdk/javascript/public_methods_unittest.cpp" ]
     include_dirs += [
       "//v8",
       "//v8/include",
     ]
   }
   configs += [ ":pdfium_core_config" ]
   if (is_android) {
     ignore_all_data_deps = true
@@ skipping 59 matching lines @@
 }
 
 if (pdf_is_standalone) {
   source_set("samples") {
     testonly = true
     deps = [
       "//samples",
     ]
   }
 }