Add GN files for chrome_elf

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 6beb8496992dc912eafacae6f7312d59cfcdfc67..212192e6167ef285faa26989d35c3c1c2d2c6402 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -898,7 +898,17 @@ if (is_win) {
     "/Oy-",  # disable omitting frame pointers, must be after /o2.
     "/Os",  # favor size over speed.
   ]
-  common_optimize_on_ldflags = []
+  if (!is_asan) {
+    common_optimize_on_cflags += [
+      # Put data in separate COMDATs. This allows the linker
+      # to put bit-identical constants at the same address even if
+      # they're unrelated constants, which saves binary size.
+      # This optimization can't be used when ASan is enabled because
+      # it is not compatible with the ASan ODR checker.
+      "/Gw",
+    ]
+  }
+  common_optimize_on_ldflags = [ "/OPT:REF" ]
 } else {
   common_optimize_on_cflags = [
     # Don't emit the GCC version ident directives, they just end up in the