GN: port a few missing Android bits from GYP.

BUILD.gn

 # Copyright 2016 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//gn/shared_sources.gni")
 
 declare_args() {
   skia_enable_tools = !is_fuchsia && !is_component_build
 
@@ skipping 60 matching lines @@
     "src/ports",
     "src/sfnt",
     "src/sksl",
     "src/utils",
     "src/utils/win",
     "third_party/etc1",
     "third_party/ktx",
   ]
 
   defines = [ "SK_GAMMA_APPLY_TO_A8" ]
+  if (is_android) {
+    defines += [
+      "SK_GAMMA_EXPONENT=1.4",
+      "SK_GAMMA_CONTRAST=0.0",
+    ]
+  }
 }
 
 # Any code that's linked into Skia-the-library should use this config via += skia_library_configs.
 config("skia_library") {
   visibility = [ ":*" ]
   defines = [ "SKIA_IMPLEMENTATION=1" ]
 }
 
 skia_library_configs = [
   ":skia_public",
@@ skipping 511 matching lines @@
 
   test_lib("tool_utils") {
     public_include_dirs = [
       "tools",
       "tools/debugger",
       "tools/timer",
     ]
     sources = [
       "src/images/SkForceLinking.cpp",
       "src/utils/SkMultiPictureDocumentReader.cpp",  # TODO(halcanary): move to tools?
+      "tools/AndroidSkDebugToStdOut.cpp",
       "tools/CrashHandler.cpp",
       "tools/LsanSuppressions.cpp",
       "tools/ProcStats.cpp",
       "tools/Resources.cpp",
       "tools/ThermalManager.cpp",
       "tools/UrlDataManager.cpp",
       "tools/debugger/SkDebugCanvas.cpp",
       "tools/debugger/SkDrawCommand.cpp",
       "tools/debugger/SkJsonWriteBuffer.cpp",
       "tools/debugger/SkObjectParser.cpp",
@@ skipping 163 matching lines @@
         "tools/using_skia_and_harfbuzz.cpp",
       ]
       deps = [
         ":skia",
         "//third_party/harfbuzz",
       ]
       testonly = true
     }
   }
 }