Enable use-after-scope check in ASAN configs.

build/config/sanitizers/BUILD.gn

Index: build/config/sanitizers/BUILD.gn
diff --git a/build/config/sanitizers/BUILD.gn b/build/config/sanitizers/BUILD.gn
index e7425461d40b6cdf5aab428f0adf66ba934dde13..643d245420ff57c47bfed1de184a2c16dda0c262 100644
--- a/build/config/sanitizers/BUILD.gn
+++ b/build/config/sanitizers/BUILD.gn
@@ -200,6 +200,9 @@ config("default_sanitizer_ldflags") {
     ldflags = []
     if (is_asan) {
       ldflags += [ "-fsanitize=address" ]
+      if (!is_mac) {

[achuithb, 2017/01/21 01:00:40]

Also not chromeos

+        ldflags += [ "-fsanitize-address-use-after-scope" ]
+      }
     }
     if (is_lsan) {
       ldflags += [ "-fsanitize=leak" ]
@@ -309,6 +312,9 @@ config("asan_flags") {
   cflags = []
   if (is_asan) {
     cflags += [ "-fsanitize=address" ]
+    if (!is_mac) {
+      cflags += [ "-fsanitize-address-use-after-scope" ]
+    }
     if (!asan_globals) {
       cflags += [
         "-mllvm",