Store USB device permissions in website settings.

components/content_settings/core/browser/content_settings_registry.cc

Index: components/content_settings/core/browser/content_settings_registry.cc
diff --git a/components/content_settings/core/browser/content_settings_registry.cc b/components/content_settings/core/browser/content_settings_registry.cc
index cfc4f65a4f9888b73769dc935c75397a256e4354..91af3a0bff7daa4e279d0fd362e1ca43afe6aa11 100644
--- a/components/content_settings/core/browser/content_settings_registry.cc
+++ b/components/content_settings/core/browser/content_settings_registry.cc
@@ -156,6 +156,9 @@ void ContentSettingsRegistry::Init() {
   Register(CONTENT_SETTINGS_TYPE_DURABLE_STORAGE, "durable-storage",
            CONTENT_SETTING_ASK, WebsiteSettingsInfo::UNSYNCABLE,
            NoWhitelistedSchemes());
+  // Register(CONTENT_SETTINGS_TYPE_USB, "usb",

[raymes, 2015/10/06 05:28:20]

I'd suggest naming this one "USB" and the website setting "USB_CHOOSER_DATA" or
something like that (establish a pattern for future devs and hopefully we can
write code to automate some of this later :)

[Reilly Grant (use Gerrit), 2015/10/06 20:45:30]

Okay. I think this will also resolve mlamouri@'s concerns about extending
PermissionContextBase. If I make ChooserPermissionContextBase the root of its
own class hierarchy then I can require that each chooser permission also
references a boolean content setting.

+  //         CONTENT_SETTING_ALLOW, WebsiteSettingsInfo::UNSYNCABLE,
+  //         NoWhitelistedSchemes());
 
   // Content settings that aren't used to store any data. TODO(raymes): use a
   // different mechanism rather than content settings to represent these.