Put the syzygy targets behind a 'syzygy_optimize' flag.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index c79e8e76ee7ce79ea4b8f3becf125a1544c84c49..32f85193e9ce631eccff1e0b39998ebf2416e47b 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -518,6 +518,9 @@
       'enable_enhanced_bookmarks%': 0,
       'enable_hangout_services_extension%': 0,
 
+       # Enable the Syzygy optimization step.
+      'syzygy_optimize%': 0,
+
       'conditions': [
         # A flag for POSIX platforms
         ['OS=="win"', {
@@ -818,9 +821,9 @@
           'enable_printing%': 0,
         }],
 
-	# By default, use ICU data file (icudtl.dat) on all platforms
-	# except when building Android WebView.
-	# TODO(jshin): Handle 'use_system_icu' on Linux (Chromium).
+        # By default, use ICU data file (icudtl.dat) on all platforms
+        # except when building Android WebView.
+        # TODO(jshin): Handle 'use_system_icu' on Linux (Chromium).
         ['android_webview_build==0', {
           'icu_use_data_file_flag%' : 1,
         }, {
@@ -939,6 +942,7 @@
     'asan%': '<(asan)',
     'asan_coverage%': '<(asan_coverage)',
     'syzyasan%': '<(syzyasan)',
+    'syzygy_optimize%': '<(syzygy_optimize)',
     'lsan%': '<(lsan)',
     'msan%': '<(msan)',
     'msan_blacklist%': '<(msan_blacklist)',
@@ -1288,6 +1292,13 @@
     'enable_new_gamepad_api%': 1,
 
     'conditions': [
+      # Enable the Syzygy optimization step for the official builds.
+      ['OS=="win" and buildtype=="Official" and syzyasan!=1', {
+        'syzygy_optimize%': 1,
+      }, {
+        'syzygy_optimize%': 0,
+      }],
+
       # The version of GCC in use, set later in platforms that use GCC and have
       # not explicitly chosen to build with clang. Currently, this means all
       # platforms except Windows, Mac and iOS.