Add neon and crc32 sources for aarch64

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.
 
 declare_args() {
   skia_enable_tools = !is_fuchsia && !is_component_build
 
   skia_use_expat = true
   skia_use_giflib = !is_fuchsia
@@ skipping 149 matching lines @@
 }
 
 is_x86 = current_cpu == "x64" || current_cpu == "x86"
 
 opts("none") {
   enabled = !is_x86
   sources = opts_gypi.none_sources
   cflags = []
 }
 
+opts("neon_sources") {

[mtklein, 2016/08/25 01:26:44]

Hmm.  It's gonna have to be a little more complicated than this.

opts("armv7") {
  enabled = target_cpu == "arm"
  sources = opts_gypi.armv7_sources
  cflags = []
}

opts("neon") {
  enabled = target_cpu == "arm"
  sources = opts_gypi.neon_sources
  cflags = [ "-mfpu=neon" ]
}

opts("arm64") {
  enabled = target_cpu == "arm64"
  sources = opts_gypi.arm64_sources
  cflags = []
}

opts("crc32") {
  enabled = target_cpu == "arm64"
  sources = opts_gypi.crc32_sources
  cflags = [ "-march=armv8-a+crc" ]
}

and the enabled bit for :none will need to change to
 enabled = !is_x86 && target_cpu != "arm" && target_cpu != "arm64"

[anmittal, 2016/08/25 03:03:58]

Done.

+  enabled = !is_x86
+  sources = opts_gypi.neon_sources
+  cflags = []
+}
+
+opts("crc32_sources") {
+  enabled = !is_x86
+  sources = opts_gypi.crc32_sources
+  cflags = []
+}
+
 opts("sse2") {
   enabled = is_x86
   sources = opts_gypi.sse2_sources
   cflags = [ "-msse2" ]
 }
 
 opts("ssse3") {
   enabled = is_x86
   sources = opts_gypi.ssse3_sources
   cflags = [ "-mssse3" ]
@@ skipping 129 matching lines @@
     "src/xml/SkXMLWriter.cpp",
   ]
 }
 
 component("skia") {
   public_configs = [ ":skia_public" ]
   configs += skia_library_configs
 
   deps = [
     ":avx",
+    ":crc32_sources",
     ":gif",
     ":jpeg",
+    ":neon_sources",
     ":none",
     ":pdf",
     ":png",
     ":sse2",
     ":sse41",
     ":sse42",
     ":ssse3",
     ":webp",
     ":xml",
   ]
@@ skipping 392 matching lines @@
       "tools/SkShaper_harfbuzz.cpp",
       "tools/using_skia_and_harfbuzz.cpp",
     ]
     deps = [
       ":skia",
       "//third_party/harfbuzz",
     ]
     testonly = true
   }
 }