Fix math round when number > 2^52 on IE11 (#832)

Don't use math round on ie11 if number > 2^52.

build/types/polyfill

@@ -2,6 +2,7 @@
 
 +../../lib/polyfill/fullscreen.js
 +../../lib/polyfill/indexed_db.js
++../../lib/polyfill/mathround.js
 +../../lib/polyfill/mediakeys.js
 +../../lib/polyfill/mediasource.js
 +../../lib/polyfill/patchedmediakeys_ms.js

lib/polyfill/mathround.js

@@ -0,0 +1,58 @@
+/**
+ * @license
+ * Copyright 2016 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+goog.provide('shaka.polyfill.MathRound');
+
+goog.require('shaka.log');
+goog.require('shaka.polyfill.register');
+
+/**
+ * @namespace shaka.polyfill.MathRound
+ *
+ * @summary A polyfill to patch math round bug on some browsers.
+ */
+
+
+/**
+ @const {number}
+ @private
+ */
+shaka.polyfill.MathRound.MAX_ACCURATE_INPUT_ = 0x10000000000000;
+
+
+/**
+ * Install the polyfill if needed.
+ */
+shaka.polyfill.MathRound.install = function() {
+  shaka.log.debug('mathRound.install');
+
+  var testNumber = shaka.polyfill.MathRound.MAX_ACCURATE_INPUT_ + 1;
+  if (Math.round(testNumber) != testNumber) {
+    shaka.log.debug('polyfill Math.round');
+    var original_mathRound = Math.round;
+    Math.round = function(number) {
+      var result = number;
+      // https://stackoverflow.com/questions/12830742/javascript-math-round-bug-in-ie
+      // Due to the precision of JavaScript numbers, the number must be integer
+      if (number <= shaka.polyfill.MathRound.MAX_ACCURATE_INPUT_) {
+        result = original_mathRound(number);
+      }
+      return result;
+    };
+  }
+};
+
+shaka.polyfill.register(shaka.polyfill.MathRound.install);

shaka-player.uncompiled.js

@@ -44,6 +44,7 @@ goog.require('shaka.offline.OfflineScheme');
 goog.require('shaka.offline.Storage');
 goog.require('shaka.polyfill.Fullscreen');
 goog.require('shaka.polyfill.IndexedDB');
+goog.require('shaka.polyfill.MathRound');
 goog.require('shaka.polyfill.MediaKeys');
 goog.require('shaka.polyfill.MediaSource');
 goog.require('shaka.polyfill.Promise');