Make DISABLE_CFI_PERF only effective in the official builds.

This is to allow regular CFI buildbot to catch any regressions in
the blacklisted code.

BUG=

Review-Url: https://codereview.chromium.org/2361623002
Cr-Commit-Position: refs/heads/master@{#420414}
diff --git a/base/compiler_specific.h b/base/compiler_specific.h
index f064be8d..0dbc3ae5 100644
--- a/base/compiler_specific.h
+++ b/base/compiler_specific.h
@@ -171,7 +171,7 @@
 
 // DISABLE_CFI_PERF -- Disable Control Flow Integrity for perf reasons.
 #if !defined(DISABLE_CFI_PERF)
-#if defined(__clang__)
+#if defined(__clang__) && defined(OFFICIAL_BUILD)
 #define DISABLE_CFI_PERF __attribute__((no_sanitize("cfi")))
 #else
 #define DISABLE_CFI_PERF