Revert "win: /utf-8 for all code"

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index 15244866768ce94459e31f87f1a2b3c1ce9e7a16..c6ea8839a08a379ce93460dd93ac60c1f20a1b8f 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -843,11 +843,6 @@ config("default_warnings") {
     }
 
     cflags += [
-      # Assume UTF-8 by default to avoid code page dependencies.
-      "/utf-8",
-    ]
-
-    cflags += [
       # Warnings permanently disabled:
 
       # C4091: 'typedef ': ignored on left of 'X' when no variable is
@@ -1078,6 +1073,9 @@ config("default_warnings") {
 config("chromium_code") {
   if (is_win) {
     cflags = [ "/W4" ]  # Warning level 4.
+
+    # Assume UTF-8 by default to avoid code page dependencies.
+    cflags += [ "/utf-8" ]
   } else {
     cflags = [ "-Wall" ]
     if (treat_warnings_as_errors) {