Add a buildflag to use the handle verifier in a per module mode.

base/base.gyp

Index: base/base.gyp
diff --git a/base/base.gyp b/base/base.gyp
index 7c9417d013c77fe9e9278e8330a35d1f3d655f19..7aac3ec9d791cdd87a70fbcd74920c8ce304f306 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -24,6 +24,7 @@
         'allocator/allocator.gyp:allocator',
         'allocator/allocator.gyp:allocator_features#target',
         'base_debugging_flags#target',
+        'base_win_features#target',
         'base_static',
         'base_build_date#target',
         '../testing/gtest.gyp:gtest_prod',
@@ -1019,7 +1020,7 @@
     },
     {
       # GN version: //base/debug:debugging_flags
-      # Since this generates a file, it most only be referenced in the target
+      # Since this generates a file, it must only be referenced in the target
       # toolchain or there will be multiple rules that generate the header.
       # When referenced from a target that might be compiled in the host
       # toolchain, always refer to 'base_debugging_flags#target'.
@@ -1033,6 +1034,27 @@
       },
     },
     {
+      # GN version: //base/win:base_win_features
+      # Since this generates a file, it must only be referenced in the target
+      # toolchain or there will be multiple rules that generate the header.
+      # When referenced from a target that might be compiled in the host
+      # toolchain, always refer to 'base_win_features#target'.
+      'target_name': 'base_win_features',
+      'conditions': [
+        ['OS=="win"', {
+          'includes': [ '../build/buildflag_header.gypi' ],
+          'variables': {
+            'buildflag_header_path': 'base/win/base_features.h',
+            'buildflag_flags': [
+              'ENABLE_HANDLE_VERIFIER=<(enable_handle_verifier)',
+            ],
+          },
+        }, {
+          'type': 'none',
+        }],
+      ],
+    },
+    {
       'type': 'none',
       'target_name': 'base_build_date',
       'hard_dependency': 1,