port cfi to gn

build/config/sanitizers/sanitizers.gni

Index: build/config/sanitizers/sanitizers.gni
diff --git a/build/config/sanitizers/sanitizers.gni b/build/config/sanitizers/sanitizers.gni
index d5374e1a0ffb83f6b019d14e05f0f65c910da7b7..c575eb1cc1f680218a6fe220ab38ae5af4b09ec6 100644
--- a/build/config/sanitizers/sanitizers.gni
+++ b/build/config/sanitizers/sanitizers.gni
@@ -22,6 +22,14 @@ declare_args() {
   # errors. Only works on Windows. See
   # https://code.google.com/p/sawbuck/wiki/SyzyASanHowTo
   is_syzyasan = false
+
+  # Compile with Control Flow Integrity to protect virtual calls and casts.
+  # See http://clang.llvm.org/docs/ControlFlowIntegrity.html
+  is_cfi = false
+
+  # By default, Control Flow Integrity will crash the program if it detects a
+  # violation. Set this to true to print detailed diagnostics instead.
+  use_cfi_diag = false
 }
 
 # MSan only links Chrome properly in release builds (brettw -- 9/1/2015). The