Import Polymer 0.8 and several key elements.

third_party/polymer/v0_8/components-chromium/paper-input/paper-input-error-extracted.js

Index: third_party/polymer/v0_8/components-chromium/paper-input/paper-input-error-extracted.js
diff --git a/third_party/polymer/v0_8/components-chromium/paper-input/paper-input-error-extracted.js b/third_party/polymer/v0_8/components-chromium/paper-input/paper-input-error-extracted.js
new file mode 100644
index 0000000000000000000000000000000000000000..e447df14180c8bf82204844d9d621ea318e86d5b
--- /dev/null
+++ b/third_party/polymer/v0_8/components-chromium/paper-input/paper-input-error-extracted.js
@@ -0,0 +1,35 @@
+
+
+(function() {
+
+  Polymer({
+
+    is: 'paper-input-error',
+
+    enableCustomStyleProperties: true,
+
+    hostAttributes: {
+      'add-on': '',
+      'role': 'alert'
+    },
+
+    properties: {
+
+      /**
+       * Set to true to show the error.
+       */
+      invalid: {
+        reflectToAttribute: true,
+        type: Boolean
+      }
+
+    },
+
+    attached: function() {
+      this.fire('addon-attached');
+    }
+
+  })
+
+})();
+