Enable Control Flow Integrity for the official Linux Chrome.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 944dcb6eebb257bf06dda0140bcd09e45face065..5f6cf4fe80d863f1963a1989f8cbdde8058cf2a7 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -849,6 +849,11 @@
           'enable_prod_wallet_service%': 1,
         }],
 
+        # Enable Control Flow Integrity for the official Linux Chrome.

[Nico, 2015/10/12 18:17:29]

nit: Maybe add a comment that this condition should match the one in update.sh,
and add one in update.sh saying that condition should match common.gypi (? not
sure if that's a good idea; feel free to ignore)

+        ['OS=="linux" and buildtype=="Official" and branding=="Chrome"', {

[Nico, 2015/10/12 18:17:29]

This will also enable this for chromeos. Is that intentional? Probably not? If
not, add `and chromeos==0`.

+          'cfi_vptr%': 1,
+        }],
+
         # Enable hotwording on Chrome-branded ChromeOS builds.
         ['branding=="Chrome" and chromeos==1', {
           'enable_hotwording%': 1,