chore(polyfill): break DOM polyfills into external file

scripts/gulp/tasks/polyfill.ts

@@ -95,11 +95,6 @@ task('polyfill.modern', (done) => {
 });
 
 task('polyfill.copy-readme', (done) => {
-  const rename = require('gulp-rename');
-
-  return src('scripts/npm/polyfills.readme.md')
-    .pipe(rename({
-      basename: 'README'
-    }))
+  return src('scripts/polyfill/readme.md')
     .pipe(dest('dist/ionic-angular/polyfills/'), done);
 });

scripts/polyfill/polyfill.dom.js

@@ -0,0 +1,30 @@
+(function(){
+  "use strict";
+
+  if (typeof Element.prototype.matches !== 'function') {
+    Element.prototype.matches = Element.prototype.msMatchesSelector || Element.prototype.webkitMatchesSelector || function matches(selector) {
+      var element = this;
+      var elements = (element.document || element.ownerDocument).querySelectorAll(selector);
+      var index = 0;
+      while (elements[index] && elements[index] !== element) {
+        ++index;
+      }
+      return Boolean(elements[index]);
+    };
+  }
+
+
+  if (typeof Element.prototype.closest !== 'function') {
+    Element.prototype.closest = function closest(selector) {
+      var element = this;
+      while (element && element.nodeType === 1) {
+        if (element.matches(selector)) {
+          return element;
+        }
+        element = element.parentNode;
+      }
+      return null;
+    };
+  }
+
+})();

src/util/dom.ts

@@ -247,32 +247,6 @@ export function copyInputAttributes(srcElement: HTMLElement, destElement: HTMLEl
   }
 }
 
-// TODO: Add to external polyfill script
-if (typeof Element.prototype.matches !== 'function') {
-  Element.prototype.matches = Element.prototype.msMatchesSelector || Element.prototype.webkitMatchesSelector || function matches(selector) {
-    var element = this;
-    var elements = (element.document || element.ownerDocument).querySelectorAll(selector);
-    var index = 0;
-    while (elements[index] && elements[index] !== element) {
-      ++index;
-    }
-    return Boolean(elements[index]);
-  };
-}
-
-if (typeof Element.prototype.closest !== 'function') {
-  Element.prototype.closest = function closest(selector) {
-    var element = this;
-    while (element && element.nodeType === 1) {
-      if (element.matches(selector)) {
-        return element;
-      }
-      element = element.parentNode;
-    }
-    return null;
-  };
-}
-
 
 /**
  * Get the element offsetWidth and offsetHeight. Values are cached