GN: add skia_enable_gpu (default true)

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index c94f3cf9dfb64d579ad8fef75afc191e1175484a..3c6ac0f462447cd4fbb40ce200843ca91c95bffc 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -6,8 +6,6 @@
 import("gn/shared_sources.gni")
 
 declare_args() {
-  skia_enable_tools = !is_fuchsia && !is_component_build
-
   skia_use_expat = true
   skia_use_fontconfig = is_linux
   skia_use_freetype = is_android || is_fuchsia || is_linux
@@ -20,8 +18,13 @@ declare_args() {
   skia_use_zlib = true
 
   skia_enable_android_framework_defines = false
+  skia_enable_gpu = true
+  skia_enable_tools = !is_fuchsia
 }
 
+# Our tools require static linking (they use non-exported symbols) and GPU support (just lazy).
+skia_enable_tools = skia_enable_tools && skia_enable_gpu && !is_component_build
+
 fontmgr_android_enabled = skia_use_expat && skia_use_freetype
 
 skia_public_includes = [
@@ -52,6 +55,9 @@ config("skia_public") {
   if (skia_enable_android_framework_defines) {
     defines += skia_android_framework_defines
   }
+  if (!skia_enable_gpu) {
+    defines += [ "SK_SUPPORT_GPU=0" ]
+  }
 }
 
 # Skia internal APIs, used by Skia itself and a few test tools.
@@ -294,6 +300,27 @@ optional("gif") {
   ]
 }
 
+optional("gpu") {
+  enabled = skia_enable_gpu
+  sources = skia_gpu_sources + [ "src/gpu/gl/GrGLDefaultInterface_native.cpp" ]
+
+  # These paths need to be absolute to match the ones produced by shared_sources.gni.
+  sources -= get_path_info([
+                             "src/gpu/gl/GrGLCreateNativeInterface_none.cpp",
+                             "src/gpu/gl/GrGLDefaultInterface_none.cpp",
+                           ],
+                           "abspath")
+  if (is_android) {
+    sources += [ "src/gpu/gl/android/GrGLCreateNativeInterface_android.cpp" ]
+  } else if (is_linux) {
+    sources += [ "src/gpu/gl/glx/GrGLCreateNativeInterface_glx.cpp" ]
+  } else if (is_mac) {
+    sources += [ "src/gpu/gl/mac/GrGLCreateNativeInterface_mac.cpp" ]
+  } else {
+    sources += [ "src/gpu/gl/GrGLCreateNativeInterface_none.cpp" ]
+  }
+}
+
 optional("jpeg") {
   enabled = skia_use_libjpeg_turbo
   public_defines = [ "SK_HAS_JPEG_LIBRARY" ]
@@ -400,6 +427,7 @@ component("skia") {
     ":fontmgr_fontconfig",
     ":fontmgr_fuchsia",
     ":gif",
+    ":gpu",
     ":jpeg",
     ":none",
     ":pdf",
@@ -417,7 +445,6 @@ component("skia") {
   sources = []
   sources += skia_core_sources
   sources += skia_effects_sources
-  sources += skia_gpu_sources
   sources += skia_sksl_sources
   sources += skia_utils_sources
   sources += [
@@ -436,7 +463,6 @@ component("skia") {
     "src/codec/SkSampler.cpp",
     "src/codec/SkSwizzler.cpp",
     "src/codec/SkWbmpCodec.cpp",
-    "src/gpu/gl/GrGLDefaultInterface_native.cpp",
     "src/images/SkImageEncoder.cpp",
     "src/images/SkImageEncoder_Factory.cpp",
     "src/images/SkKTXImageEncoder.cpp",
@@ -454,15 +480,6 @@ component("skia") {
     "third_party/ktx/ktx.cpp",
   ]
 
-  # These paths need to be absolute to match the ones produced by
-  # shared_sources.gni, but this file may be used from different directory
-  # locations.
-  sources -= get_path_info([
-                             "src/gpu/gl/GrGLCreateNativeInterface_none.cpp",
-                             "src/gpu/gl/GrGLDefaultInterface_none.cpp",
-                           ],
-                           "abspath")
-
   libs = []
 
   if (is_win) {
@@ -494,10 +511,7 @@ component("skia") {
       "//third_party/cpu-features",
       "//third_party/expat",
     ]
-    sources += [
-      "src/gpu/gl/android/GrGLCreateNativeInterface_android.cpp",
-      "src/ports/SkDebug_android.cpp",
-    ]
+    sources += [ "src/ports/SkDebug_android.cpp" ]
     libs += [
       "EGL",
       "GLESv2",
@@ -511,15 +525,11 @@ component("skia") {
       "GLU",
       "X11",
     ]
-    sources += [
-      "src/gpu/gl/glx/GrGLCreateNativeInterface_glx.cpp",
-      "src/ports/SkDebug_stdio.cpp",
-    ]
+    sources += [ "src/ports/SkDebug_stdio.cpp" ]
   }
 
   if (is_mac) {
     sources += [
-      "src/gpu/gl/mac/GrGLCreateNativeInterface_mac.cpp",
       "src/ports/SkDebug_stdio.cpp",
       "src/ports/SkFontHost_mac.cpp",
       "src/ports/SkImageEncoder_CG.cpp",
@@ -532,10 +542,7 @@ component("skia") {
   }
 
   if (is_fuchsia) {
-    sources += [
-      "src/gpu/gl/GrGLCreateNativeInterface_none.cpp",
-      "src/ports/SkDebug_stdio.cpp",
-    ]
+    sources += [ "src/ports/SkDebug_stdio.cpp" ]
   }
 }
 
@@ -561,7 +568,7 @@ action("skia.h") {
   ]
 }
 
-if (target_cpu == "x64") {
+if (skia_enable_gpu && target_cpu == "x64") {
   # Our bots only have 64-bit libOSMesa installed.
   # TODO: worth fixing?
   executable("fiddle") {