Cleanup: Remove most enable_extensions logic in extensions code.

extensions/common/permissions/usb_device_permission.cc

Index: extensions/common/permissions/usb_device_permission.cc
diff --git a/extensions/common/permissions/usb_device_permission.cc b/extensions/common/permissions/usb_device_permission.cc
index cd035d42061bbdf51e524ec889b13feb367b5480..c482e8625ed97314f72664099c311d8a231e2e2a 100644
--- a/extensions/common/permissions/usb_device_permission.cc
+++ b/extensions/common/permissions/usb_device_permission.cc
@@ -10,14 +10,11 @@
 #include "base/logging.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
+#include "device/usb/usb_ids.h"
 #include "extensions/common/permissions/permissions_info.h"
 #include "grit/extensions_strings.h"
 #include "ui/base/l10n/l10n_util.h"
 
-#if defined(ENABLE_EXTENSIONS)
-#include "device/usb/usb_ids.h"
-#endif
-
 namespace extensions {
 
 UsbDevicePermission::UsbDevicePermission(
@@ -33,7 +30,6 @@ PermissionMessages UsbDevicePermission::GetMessages() const {
   DCHECK(HasMessages());
   PermissionMessages result;
 
-#if defined(ENABLE_EXTENSIONS)
   // //device/usb/usb.gyp:device_usb is not available when extensions are
   // disabled.
   for (std::set<UsbDevicePermissionData>::const_iterator i =
@@ -64,9 +60,6 @@ PermissionMessages UsbDevicePermission::GetMessages() const {
               IDS_EXTENSION_PROMPT_WARNING_USB_DEVICE_MISSING_VENDOR)));
     }
   }
-#else
-  NOTREACHED();
-#endif  // defined(ENABLE_EXTENSIONS)
 
   return result;
 }