[canvaskit] Fix debug build for CanvasKit (#162198)

Fixes the debug build for CanvasKit.

NOTE: We need to build the debug WASM build with `-O1` because building
with `-O0` causes Emscripten to produce a binary that is rejected by
Chrome for having functions with too many local variables. Building with
`-O1` optimizes those locals out.

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engine/src/build/config/compiler/BUILD.gn

@@ -933,6 +933,14 @@ config("no_optimize") {
       cflags += [ "-fomit-frame-pointer" ]
     }
     ldflags = common_optimize_on_ldflags
+  } else if (is_wasm) {
+    # On WASM we don't want to fully deoptimize the debug build because the
+    # compiled binary will have some functions with too many local variables
+    # and Chrome will reject it.
+    cflags = [
+      "-O1",
+    ]
+    ldflags = common_optimize_on_ldflags
   } else {
     cflags = [ "-O0" ]
   }

engine/src/flutter/skia/modules/canvaskit/BUILD.gn

@@ -62,7 +62,7 @@ canvaskit_wasm_lib("canvaskit") {
   ldflags = []
   if (is_debug) {
     ldflags += [
-      "-O0",
+      "-O1",
       "-sASSERTIONS=1",
       "-sGL_ASSERTIONS=1",
       "-g3",
@@ -110,14 +110,14 @@ canvaskit_wasm_lib("canvaskit") {
     "--bind",
     "--no-entry",
     "--pre-js",
+    rebase_path("$_skia_root/modules/canvaskit/util.js"),
+    "--pre-js",
     rebase_path("$_skia_root/modules/canvaskit/preamble.js"),
     "--pre-js",
     rebase_path("$_skia_root/modules/canvaskit/color.js"),
     "--pre-js",
     rebase_path("$_skia_root/modules/canvaskit/memory.js"),
     "--pre-js",
-    rebase_path("$_skia_root/modules/canvaskit/util.js"),
-    "--pre-js",
     rebase_path("$_skia_root/modules/canvaskit/interface.js"),
   ]
 
@@ -164,7 +164,7 @@ canvaskit_wasm_lib("canvaskit") {
     "-sEXPORT_NAME=CanvasKitInit",
     "-sEXPORTED_FUNCTIONS=[_malloc,_free]",
     "-sEXPORTED_RUNTIME_METHODS=HEAP8,HEAPU8,HEAP16,HEAPU16,HEAP32,HEAPF32,HEAPU32,HEAPF64",
-    "-sINCOMING_MODULE_JS_API=onRuntimeInitialized",
+    "-sINCOMING_MODULE_JS_API=[instantiateWasm,onRuntimeInitialized,noExitRuntime]",
     "-sFORCE_FILESYSTEM=0",
     "-sFILESYSTEM=0",
     "-sMODULARIZE",