Inline GPU and opus GYP files into GN build.

.gn

Index: .gn
diff --git a/.gn b/.gn
index 172de2ff9e81a41aa861aa5fca1b2d0db6213f08..f6ddb4534aa3d1df7a5cd763a776c74959981f2d 100644
--- a/.gn
+++ b/.gn
@@ -260,9 +260,6 @@ exec_script_whitelist = [
   "//content/browser/browser.gni",
   "//content/public/android/BUILD.gn",
   "//content/test/BUILD.gn",
-  "//google_apis/BUILD.gn",
-  "//gpu/gles2_conform_support/BUILD.gn",
-  "//gpu/khronos_glcts_support/BUILD.gn",
   "//jingle/BUILD.gn",
   "//net/BUILD.gn",
   "//printing/BUILD.gn",
@@ -279,7 +276,6 @@ exec_script_whitelist = [
   "//third_party/google_input_tools/inputview.gni",
   "//third_party/harfbuzz-ng/BUILD.gn",
   "//third_party/libaddressinput/BUILD.gn",
-  "//third_party/opus/BUILD.gn",
   "//third_party/openh264/BUILD.gn",
   "//third_party/skia/gn/shared_sources.gni",
   "//third_party/WebKit/Source/bindings/bindings.gni",
@@ -289,21 +285,11 @@ exec_script_whitelist = [
   "//third_party/WebKit/Source/modules/modules.gni",
   "//third_party/WebKit/Source/web/BUILD.gn",
   "//tools/gn/BUILD.gn",
-  "//tools/gn/build_settings.h",
-  "//tools/gn/command_help.cc",
-  "//tools/gn/docs/language.md",
-  "//tools/gn/format_test_data/053.gn",
-  "//tools/gn/format_test_data/053.golden",
-  "//tools/gn/format_test_data/055.gn",
-  "//tools/gn/format_test_data/055.golden",
-  "//tools/gn/function_exec_script.cc",
-  "//tools/gn/gn.gyp",
-  "//tools/gn/input_conversion.cc",
-  "//tools/gn/misc/emacs/gn.el",
-  "//tools/gn/misc/vim/syntax/gn.vim",
-  "//tools/gn/setup.cc",
   "//ui/accessibility/BUILD.gn",
   "//ui/gfx/BUILD.gn",
   "//v8/test/cctest/BUILD.gn",
   "//v8/test/unittests/BUILD.gn",
+
+  # Not gypi-to-gn.
+  "//google_apis/BUILD.gn",
 ]