Override the WASM toolchain to use CanvasKit-specific args

build/toolchain/gcc_toolchain.gni

@@ -291,6 +291,10 @@ template("gcc_toolchain") {
       if (defined(invoker.is_clang)) {
         is_clang = invoker.is_clang
       }
+
+      if (defined(invoker.extra_toolchain_args)) {
+        forward_variables_from(invoker.extra_toolchain_args, "*")
+      }
     }
 
     if (defined(invoker.deps)) {

build/toolchain/wasm/BUILD.gn

@@ -17,7 +17,10 @@ if (use_goma) {
   compiler_prefix = ""
 }
 
-gcc_toolchain("wasm") {
+# This toolchain is specifically for building CanvasKit.
+#
+# It overrides many Skia args in order to facilitate building CanvasKit.
+gcc_toolchain("wasm_for_canvaskit") {
   # emsdk_dir and em_config are defined in wasm.gni.
   ar = "$compiler_prefix$emsdk_dir/upstream/emscripten/emar --em-config $em_config_path"
   cc = "$compiler_prefix$emsdk_dir/upstream/emscripten/emcc --em-config $em_config_path"
@@ -32,4 +35,47 @@ gcc_toolchain("wasm") {
   is_clang = true
 
   link_outputs = [ "{{root_out_dir}}/{{target_output_name}}.wasm" ]
+
+  extra_toolchain_args = {
+    skia_use_vulkan = false
+    skia_use_webgpu = false
+    skia_use_libheif = false
+    skia_use_libjpeg_turbo_decode = true
+    skia_use_libjpeg_turbo_encode = false
+    skia_use_libpng_decode = true
+    skia_use_libpng_encode = true
+    skia_use_libwebp_decode = true
+    skia_use_libwebp_encode = false
+    skia_use_lua = false
+    skia_use_wuffs = true
+    skia_use_zlib = true
+    skia_gl_standard = "webgl"
+    skia_enable_gpu = true
+    skia_enable_sksl_tracing = false
+    skia_use_icu = true
+    skia_use_harfbuzz = true
+    skia_enable_fontmgr_custom_directory = false
+    skia_enable_fontmgr_custom_embedded = true
+    skia_enable_fontmgr_custom_empty = false
+    skia_enable_skshaper = true
+    skia_enable_skparagraph = true
+    skia_canvaskit_force_tracing = false
+    skia_canvaskit_enable_skp_serialization = true
+    skia_canvaskit_enable_effects_deserialization = false
+    skia_canvaskit_enable_skottie = false
+    skia_canvaskit_include_viewer = false
+    skia_canvaskit_enable_particles = false
+    skia_canvaskit_enable_pathops = true
+    skia_canvaskit_enable_rt_shader = true
+    skia_canvaskit_enable_matrix_helper = false
+    skia_canvaskit_enable_canvas_bindings = false
+    skia_canvaskit_enable_font = true
+    skia_canvaskit_enable_embedded_font = true
+    skia_canvaskit_enable_alias_font = true
+    skia_canvaskit_legacy_draw_vertices_blend_mode = false
+    skia_canvaskit_enable_debugger = false
+    skia_canvaskit_enable_paragraph = true
+    skia_canvaskit_enable_webgl = true
+    skia_canvaskit_enable_webgpu = false
+  }
 }