[Windows MSVC CFG] Add support for CFG, and enable on chrome.exe & chrome_elf.dll.

build/config/win/BUILD.gn

Index: build/config/win/BUILD.gn
diff --git a/build/config/win/BUILD.gn b/build/config/win/BUILD.gn
index 9b6ac7423f2b9d4d12bdea8302a200507d706e6e..1ec92c64cc86b52d19867208dbd792c6ceb20136 100644
--- a/build/config/win/BUILD.gn
+++ b/build/config/win/BUILD.gn
@@ -264,6 +264,18 @@ config("common_linker_setup") {
   }
 }
 
+config("win_msvc_cfg") {

[scottmg, 2016/10/13 21:40:06]

Also a brief comment here with an MSDN link for those unfamiliar, as "CFG" is a
bit of a generic acronym.

[penny, 2016/10/13 22:08:30]

Done.

+  if (visual_studio_version == "2015" && !is_clang) {

[scottmg, 2016/10/13 21:38:12]

You can drop the version check, 2013 won't work for a lot of other reasons, and
I assume this will be supported for VS 2017 or whatever.

[penny, 2016/10/13 22:08:30]

Done.

+    cflags = [ "/guard:cf" ]
+  }
+
+  # /DYNAMICBASE (ASLR) is turned off in debug builds,
+  # therefore CFG can’t be turned on either.
+  if (!is_debug && !is_clang) {
+    ldflags = [ "/guard:cf" ]

[scottmg, 2016/10/13 21:38:12]

Doesn't seem much point in having /guard:cf passed to the compiler if it's not
passed to the linker. Just merge into one if?

[penny, 2016/10/13 22:08:30]

Done.

+  }
+}
+
 # CRT --------------------------------------------------------------------------
 
 # Configures how the runtime library (CRT) is going to be used.