Adding macro to enable changing SSL library (Part 1)

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index a73eb1be2326fc078a816366fdf1d0ab0663f584..b4a73bd4ee8b7f96eb7c3c401ddcec552b372813 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -740,6 +740,15 @@
           'use_nss_certs%': 0,
         }],
 
+        # NSS verifier usage.
+        # On non-OpenSSL iOS configurations, certificates use the operating
+        # system library, but the verifier uses the bundled copy of NSS.
+        ['(OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="solaris") or (OS=="ios" and use_openssl==0)', {
+          'use_nss_verifier%': 1,
+        }, {
+          'use_nss_verifier%': 0,
+        }],
+
         # libudev usage.  This currently only affects the content layer.
         ['OS=="linux" and embedded==0', {
           'use_udev%': 1,
@@ -1146,6 +1155,7 @@
     'use_openssl%': '<(use_openssl)',
     'use_openssl_certs%': '<(use_openssl_certs)',
     'use_nss_certs%': '<(use_nss_certs)',
+    'use_nss_verifier%': '<(use_nss_verifier)',
     'use_udev%': '<(use_udev)',
     'os_bsd%': '<(os_bsd)',
     'os_posix%': '<(os_posix)',
@@ -2112,6 +2122,9 @@
       ['use_nss_certs==1', {
         'grit_defines': ['-D', 'use_nss_certs'],
       }],
+      ['use_nss_verifier==1', {
+        'grit_defines': ['-D', 'use_nss_verifier'],
+      }],
       ['use_ozone==1', {
         'grit_defines': ['-D', 'use_ozone'],
       }],
@@ -3073,6 +3086,9 @@
       ['<(use_nss_certs)==1 and >(nacl_untrusted_build)==0', {
         'defines': ['USE_NSS_CERTS=1'],
       }],
+      ['<(use_nss_verifier)==1 and >(nacl_untrusted_build)==0', {
+        'defines': ['USE_NSS_VERIFIER=1'],
+      }],
       ['<(chromeos)==1 and >(nacl_untrusted_build)==0', {
         'defines': ['OS_CHROMEOS=1'],
       }],