Revert "Build Observatory with runtime"

runtime/bin/vmservice/observatory/deployed/web/packages/polymer/src/js/use_native_dartium_shadowdom.js

Index: runtime/bin/vmservice/observatory/deployed/web/packages/polymer/src/js/use_native_dartium_shadowdom.js
diff --git a/runtime/bin/vmservice/observatory/deployed/web/packages/polymer/src/js/use_native_dartium_shadowdom.js b/runtime/bin/vmservice/observatory/deployed/web/packages/polymer/src/js/use_native_dartium_shadowdom.js
new file mode 100644
index 0000000000000000000000000000000000000000..7b492b79bad1088d5d1cb7b95985064da95929f0
--- /dev/null
+++ b/runtime/bin/vmservice/observatory/deployed/web/packages/polymer/src/js/use_native_dartium_shadowdom.js
@@ -0,0 +1,29 @@
+// Prevent polyfilled JS Shadow DOM in Dartium
+// We need this if we want Dart code to be able to interoperate with Polymer.js
+// code that also uses Shadow DOM.
+// TODO(jmesserly): we can remove this code once platform.js is correctly
+// feature detecting Shadow DOM in Dartium.
+if (navigator.userAgent.indexOf('(Dart)') !== -1) {
+  window.Platform = window.Platform || {};
+  Platform.flags = Platform.flags || {};
+  Platform.flags.shadow = 'native';
+
+  // Note: Dartium 34 hasn't turned on the unprefixed Shadow DOM
+  // (this happens in Chrome 35), so unless "enable experimental platform
+  // features" is enabled, things will break. So we expose them as unprefixed
+  // names instead.
+  var proto = Element.prototype;
+  if (!proto.createShadowRoot) {
+    proto.createShadowRoot = proto.webkitCreateShadowRoot;
+
+    Object.defineProperty(proto, 'shadowRoot', {
+      get: function() {
+        return this.webkitShadowRoot;
+      },
+      set: function(value) {
+        this.webkitShadowRoot = value;
+      },
+      configurable: true
+    });
+  }
+}