Add support for Dr memory in the GN build.

build/gyp_chromium

Index: build/gyp_chromium
diff --git a/build/gyp_chromium b/build/gyp_chromium
index b8b328e534ac66be0d8ec06deaf642203961df45..0a015347496ea9e3d09393aeb50af963d001daf9 100755
--- a/build/gyp_chromium
+++ b/build/gyp_chromium
@@ -173,11 +173,13 @@ def GetArgsStringForGN(supplemental_files):
   remap_cases = [
       ('android_webview_build', '1', 'is_android_webview_build=true'),
       ('branding', 'Chrome', 'is_chrome_branded=true'),
+      ('build_for_tool', 'drmemory', 'disable_iterator_debugging=true'),
+      ('build_for_tool', 'tsan', 'disable_iterator_debugging=true'),
       ('buildtype', 'Official', 'is_official_build=true'),
       ('component', 'shared_library', 'is_component_build=true'),
       ('clang', '1', 'is_clang=true'),
       ('clang_use_chrome_plugins', '0', 'clang_use_chrome_plugins=false'),
-      ('disable_glibcxx_debug', '1', 'disable_glibcxx_debug=true'),
+      ('disable_glibcxx_debug', '1', 'disable_iterator_debugging=true'),
       ('target_arch', 'ia32', 'cpu_arch="x86"'),
       ('target_arch', 'x64', 'cpu_arch="x64" force_win64=true'),
       ('target_arch', 'arm', 'cpu_arch="arm"'),