GN: Fix Debug flags. Fix Windows build.

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 if (current_cpu == "arm") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
   import("//build/config/mips.gni")
@@ skipping 702 matching lines @@
       common_optimize_on_ldflags += [ "-Wl,--as-needed" ]
     }
   }
 }
 
 # Default "optimization on" config. On Windows, this favors size over speed.
 config("optimize") {
   if (is_win) {
     # Favor size over speed, /O1 must be before the common flags. The GYP
     # build also specifies /Os and /GF but these are implied by /O1.
-    cflags = [ "/O1" ] + common_optimize_on_cflags + [ "/Oi" ]
+    cflags = [ "/O2" ] + common_optimize_on_cflags + [ "/Oi" ]
   } else if (is_android) {
     cflags = [ "-Os" ] + common_optimize_on_cflags  # Favor size over speed.
   } else {
     cflags = [ "-O3" ] + common_optimize_on_cflags
   }
   ldflags = common_optimize_on_ldflags
 }
 
 # Turn off optimizations.
 config("no_optimize") {
   if (is_win) {
     cflags = [
-      "/Od",  # Disable optimization.
+      "/O2",  # Do some optimizations.
+      "/Oy-",  # Disable omitting frame pointers, must be after /O2.
       "/Ob0",  # Disable all inlining (on by default).
-      "/RTC1",  # Runtime checks for stack frame and uninitialized variables.
     ]
   } else if (is_android) {
     # On Android we kind of optimize some things that don't affect debugging
     # much even when optimization is disabled to get the binary size down.
     cflags = [
       "-Os",
       "-fdata-sections",
       "-ffunction-sections",
     ]
     ldflags = common_optimize_on_ldflags
@@ skipping 17 matching lines @@
       cflags = [ "/Zi" ]  # Produce PDB file, no edit and continue.
     }
     ldflags = [ "/DEBUG" ]
   } else {
     cflags = [
       "-g3",
       "-ggdb3",
     ]
   }
 }