Add kOsMac to the enable-password-generation supported platforms.

BUG=394303

Review URL: https://codereview.chromium.org/489493002

Cr-Commit-Position: refs/heads/master@{#291455}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@291455 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/about_flags.cc

@@ -1077,7 +1077,7 @@ const Experiment kExperiments[] = {
     "enable-password-generation",
     IDS_FLAGS_ENABLE_PASSWORD_GENERATION_NAME,
     IDS_FLAGS_ENABLE_PASSWORD_GENERATION_DESCRIPTION,
-    kOsWin | kOsLinux | kOsCrOS,
+    kOsWin | kOsLinux | kOsCrOS | kOsMac,
     ENABLE_DISABLE_VALUE_TYPE(autofill::switches::kEnablePasswordGeneration,
                               autofill::switches::kDisablePasswordGeneration)
   },