Making almost all dom_ methods private. Exceptions will be addressed in a later CL.

tools/dom/src/Device.dart

Index: tools/dom/src/Device.dart
diff --git a/sdk/lib/html/html_common/device.dart b/tools/dom/src/Device.dart
similarity index 98%
rename from sdk/lib/html/html_common/device.dart
rename to tools/dom/src/Device.dart
index fe9ad358fe1368d8da6bf91c708cf7651accb5ed..fdcaaad8ecab5efb016940f819d434157316b9b4 100644
--- a/sdk/lib/html/html_common/device.dart
+++ b/tools/dom/src/Device.dart
@@ -104,7 +104,7 @@ class Device {
   static bool isEventTypeSupported(String eventType) {
     // Browsers throw for unsupported event names.
     try {
-      var e = document.$dom_createEvent(eventType);
+      var e = document._createEvent(eventType);
       return e is Event;
     } catch (_) { }
     return false;