gn win: Enable exceptions for pdfium build

build/config/BUILDCONFIG.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.
 
 # =============================================================================
 # BUILD FLAGS
 # =============================================================================
 #
 # This block lists input arguments to the build, along with their default
 # values. GN requires listing them explicitly so it can validate input and have
@@ skipping 306 matching lines @@
   "//build/config/compiler:no_rtti",
   "//build/config/compiler:runtime_library",
 ]
 if (is_win) {
   _native_compiler_configs += [
     "//build/config/win:lean_and_mean",
     "//build/config/win:nominmax",
     "//build/config/win:sdk",
     "//build/config/win:unicode",
   ]
+  if (is_component_build) {
+    _native_compiler_configs += [ "//build/config/compiler:exceptions" ]

[Nico, 2014/07/31 23:15:23]

This isn't right, see https://codereview.chromium.org/419973003/ (or that change
is wrong, I suppose)

[scottmg, 2014/07/31 23:24:31]

OK, this is mostly just a port of existing behaviour, so I'm going to let it go
as pdfium can't roll until this lands (because I moved the posix one).

So we don't have any reason to enable exceptions any longer? Or just not based
on shared/static?

+  } else {
+    # We don't use exceptions, and when we link statically we can just get
+    # rid of them entirely.
+    _native_compiler_configs += [ "//build/config/compiler:no_exceptions" ]
+  }
 }
 if (is_posix) {
   _native_compiler_configs += [
-    "//build/config/gcc:no_exceptions",
+    "//build/config/compiler:no_exceptions",
     "//build/config/gcc:symbol_visibility_hidden",
   ]
 }
 
 if (is_linux) {
   _native_compiler_configs += [ "//build/config/linux:sdk", ]
 } else if (is_mac) {
   _native_compiler_configs += [ "//build/config/mac:sdk", ]
 } else if (is_ios) {
   _native_compiler_configs += [ "//build/config/ios:sdk", ]
@@ skipping 129 matching lines @@
     host_toolchain = "//build/toolchain/linux:$build_cpu_arch"
     set_default_toolchain("//build/toolchain/linux:$cpu_arch")
   }
 } else if (is_mac) {
   host_toolchain = "//build/toolchain/mac:clang"
   set_default_toolchain(host_toolchain)
 } else if (is_ios) {
   host_toolchain = "//build/toolchain/mac:host_clang"
   set_default_toolchain("//build/toolchain/mac:clang")
 }