lib/angular/js/ng/sniffer.js
function $SnifferProvider() {
  this.$get = ['$window', '$document', function($window, $document) {
    var eventSupport = {},
        android =
          int((/android (\d+)/.exec(lowercase(($window.navigator || {}).userAgent)) || [])[1]),
        boxee = /Boxee/i.test(($window.navigator || {}).userAgent),
        document = $document[0] || {},
        documentMode = document.documentMode,
        vendorPrefix,
        vendorRegex = /^(Moz|webkit|O|ms)(?=[A-Z])/,
        bodyStyle = document.body && document.body.style,
        transitions = false,
        animations = false,
        match;

    if (bodyStyle) {
      for(var prop in bodyStyle) {
        if(match = vendorRegex.exec(prop)) {
          vendorPrefix = match[0];
          vendorPrefix = vendorPrefix.substr(0, 1).toUpperCase() + vendorPrefix.substr(1);
          break;
        }
      }

      if(!vendorPrefix) {
        vendorPrefix = ('WebkitOpacity' in bodyStyle) && 'webkit';
      }

      transitions = !!(('transition' in bodyStyle) || (vendorPrefix + 'Transition' in bodyStyle));
      animations  = !!(('animation' in bodyStyle) || (vendorPrefix + 'Animation' in bodyStyle));

      if (android && (!transitions||!animations)) {
        transitions = isString(document.body.style.webkitTransition);
        animations = isString(document.body.style.webkitAnimation);
      }
    }


    return {
      // Android has history.pushState, but it does not update location correctly
      // so let's not use the history API at all.
      // http://code.google.com/p/android/issues/detail?id=17471
      // https://github.com/angular/angular.js/issues/904

      // older webkit browser (533.9) on Boxee box has exactly the same problem as Android has
      // so let's not use the history API also
      // We are purposefully using `!(android < 4)` to cover the case when `android` is undefined
      // jshint -W018
      history: !!($window.history && $window.history.pushState && !(android < 4) && !boxee),
      // jshint +W018
      hashchange: 'onhashchange' in $window &&
                  // IE8 compatible mode lies
                  (!documentMode || documentMode > 7),
      hasEvent: function(event) {
        // IE9 implements 'input' event it's so fubared that we rather pretend that it doesn't have
        // it. In particular the event is not fired when backspace or delete key are pressed or
        // when cut operation is performed.
        if (event == 'input' && msie == 9) return false;

        if (isUndefined(eventSupport[event])) {
          var divElm = document.createElement('div');
          eventSupport[event] = 'on' + event in divElm;
        }

        return eventSupport[event];
      },
      csp: csp(),
      vendorPrefix: vendorPrefix,
      transitions : transitions,
      animations : animations,
      android: android,
      msie : msie,
      msieDocumentMode: documentMode
    };
  }];
}
function $SnifferProvider() {
  this.$get = ['$window', '$document', function($window, $document) {
    var eventSupport = {},
        android =
          int((/android (\d+)/.exec(lowercase(($window.navigator || {}).userAgent)) || [])[1]),
        boxee = /Boxee/i.test(($window.navigator || {}).userAgent),
        document = $document[0] || {},
        documentMode = document.documentMode,
        vendorPrefix,
        vendorRegex = /^(Moz|webkit|O|ms)(?=[A-Z])/,
        bodyStyle = document.body && document.body.style,
        transitions = false,
        animations = false,
        match;

    if (bodyStyle) {
      for(var prop in bodyStyle) {
        if(match = vendorRegex.exec(prop)) {
          vendorPrefix = match[0];
          vendorPrefix = vendorPrefix.substr(0, 1).toUpperCase() + vendorPrefix.substr(1);
          break;
        }
      }

      if(!vendorPrefix) {
        vendorPrefix = ('WebkitOpacity' in bodyStyle) && 'webkit';
      }

      transitions = !!(('transition' in bodyStyle) || (vendorPrefix + 'Transition' in bodyStyle));
      animations  = !!(('animation' in bodyStyle) || (vendorPrefix + 'Animation' in bodyStyle));

      if (android && (!transitions||!animations)) {
        transitions = isString(document.body.style.webkitTransition);
        animations = isString(document.body.style.webkitAnimation);
      }
    }


    return {
      // Android has history.pushState, but it does not update location correctly
      // so let's not use the history API at all.
      // http://code.google.com/p/android/issues/detail?id=17471
      // https://github.com/angular/angular.js/issues/904

      // older webkit browser (533.9) on Boxee box has exactly the same problem as Android has
      // so let's not use the history API also
      // We are purposefully using `!(android < 4)` to cover the case when `android` is undefined
      // jshint -W018
      history: !!($window.history && $window.history.pushState && !(android < 4) && !boxee),
      // jshint +W018
      hashchange: 'onhashchange' in $window &&
                  // IE8 compatible mode lies
                  (!documentMode || documentMode > 7),
      hasEvent: function(event) {
        // IE9 implements 'input' event it's so fubared that we rather pretend that it doesn't have
        // it. In particular the event is not fired when backspace or delete key are pressed or
        // when cut operation is performed.
        if (event == 'input' && msie == 9) return false;

        if (isUndefined(eventSupport[event])) {
          var divElm = document.createElement('div');
          eventSupport[event] = 'on' + event in divElm;
        }

        return eventSupport[event];
      },
      csp: csp(),
      vendorPrefix: vendorPrefix,
      transitions : transitions,
      animations : animations,
      android: android,
      msie : msie,
      msieDocumentMode: documentMode
    };
  }];
}
!!! This is an undocumented "private" service !!!

@name $sniffer
@requires $window
@requires $document

@property {boolean} history Does the browser support html5 history api ?
@property {boolean} hashchange Does the browser support hashchange event ?
@property {boolean} transitions Does the browser support CSS transition events ?
@property {boolean} animations Does the browser support CSS animation events ?

@description
This is very simple implementation of testing browser's features.