Allow using goma on Windows with symbol_level == 2

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")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 1562 matching lines @@
 #
 # You can override the symbol level on a per-target basis by removing the
 # default config and then adding the named one you want:
 #
 #   configs -= [ "//build/config/compiler:default_symbols" ]
 #   configs += [ "//build/config/compiler:symbols" ]
 
 # Full symbols.
 config("symbols") {
   if (is_win) {
-    cflags = [ "/Zi" ]  # Produce PDB file, no edit and continue.
+    if (use_goma) {
+      # Note that this requires is_win_fastlink, enforced elsewhere.
+      cflags = [ "/Z7" ]  # Debug information in the .obj files.

[scottmg, 2017/02/01 21:56:43]

Can you not just set is_win_fastlink here instead of asserting in the other
location? (That's really a question, I don't know if it'll work or not.)

[grt (UTC plus 2), 2017/02/01 22:06:37]

1) You are awesome, Bruce. I was just searching for goma advice and came across
this CL.
2) I like the idea of flipping one switch to get sane behavior rather than
instructions like "set A and B to get cool feature". I believe that other GN
knobs work this way, so I hope it's possible here.

+    } else {
+      cflags = [ "/Zi" ]  # Produce PDB file, no edit and continue.
+    }
 
     if (is_win_fastlink) {
       # Tell VS 2015+ to create a PDB that references debug
       # information in .obj and .lib files instead of copying
       # it all. This flag is incompatible with /PROFILE
       ldflags = [ "/DEBUG:FASTLINK" ]
     } else {
       ldflags = [ "/DEBUG" ]
     }
 
@@ skipping 85 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }