chore(*): cleanup msie handling; add support comments

1. The conditions checking the msie variable value have been simplified.
There is e.g. no point to check if `msie <= 11` since there IE 12 won't ever
exist.
2. Edge UA-sniffing has been added to tests (only!) where appropriate
3. Support comments for IE/Edge have been added.

Closes #15407

Author: mgol

Diff for: src/Angular.js

@@ -169,6 +169,7 @@ var
     angularModule,
     uid               = 0;
 
+// Support: IE 9-11 only
 /**
  * documentMode is an IE-only property
  * http://msdn.microsoft.com/en-us/library/ie/cc196988(v=vs.85).aspx
@@ -1279,6 +1280,7 @@ function fromJson(json) {
 
 var ALL_COLONS = /:/g;
 function timezoneToOffset(timezone, fallback) {
+  // Support: IE 9-11 only, Edge 13-14+
   // IE/Edge do not "understand" colon (`:`) in timezone
   timezone = timezone.replace(ALL_COLONS, '');
   var requestedTimezoneOffset = Date.parse('Jan 01, 1970 00:00:00 ' + timezone) / 60000;

Diff for: src/auto/injector.js

@@ -849,8 +849,9 @@ function createInjector(modulesToLoad, strictDi) {
     }
 
     function isClass(func) {
+      // Support: IE 9-11 only
       // IE 9-11 do not support classes and IE9 leaks with the code below.
-      if (msie <= 11 || typeof func !== 'function') {
+      if (msie || typeof func !== 'function') {
         return false;
       }
       var result = func.$$ngIsClass;

Diff for: src/ng/compile.js

@@ -1959,6 +1959,7 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
       for (var i = 0; i < nodeList.length; i++) {
         attrs = new Attributes();
 
+        // Support: IE 11 only
         // Workaround for #11781 and #14924
         if (msie === 11) {
           mergeConsecutiveTextNodes(nodeList, i, notLiveList);

Diff for: src/ng/directive/attrs.js

@@ -426,10 +426,11 @@ forEach(['src', 'srcset', 'href'], function(attrName) {
 
           attr.$set(name, value);
 
-          // on IE, if "ng:src" directive declaration is used and "src" attribute doesn't exist
+          // Support: IE 9-11 only
+          // On IE, if "ng:src" directive declaration is used and "src" attribute doesn't exist
           // then calling element.setAttribute('src', 'foo') doesn't do anything, so we need
           // to set the property as well to achieve the desired effect.
-          // we use attr[attrName] value since $set can sanitize the url.
+          // We use attr[attrName] value since $set can sanitize the url.
           if (msie && propName) element.prop(propName, attr[name]);
         });
       }

Diff for: src/ng/rootScope.js

@@ -105,6 +105,7 @@ function $RootScopeProvider() {
 
     function cleanUpScope($scope) {
 
+      // Support: IE 9 only
       if (msie === 9) {
         // There is a memory leak in IE9 if all child scopes are not disconnected
         // completely when a scope is destroyed. So this code will recurse up through

Diff for: src/ng/sce.js

@@ -748,6 +748,7 @@ function $SceProvider() {
 
   this.$get = ['$parse', '$sceDelegate', function(
                 $parse,   $sceDelegate) {
+    // Support: IE 9-11 only
     // Prereq: Ensure that we're not running in IE<11 quirks mode.  In that mode, IE < 11 allow
     // the "expression(javascript expression)" syntax which is insecure.
     if (enabled && msie < 8) {

Diff for: src/ng/sniffer.js

@@ -57,12 +57,13 @@ function $SnifferProvider() {
       // We are purposefully using `!(android < 4)` to cover the case when `android` is undefined
       history: !!(hasHistoryPushState && !(android < 4) && !boxee),
       hasEvent: function(event) {
+        // Support: IE 9-11 only
         // 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.
         // IE10+ implements 'input' event but it erroneously fires under various situations,
         // e.g. when placeholder changes, or a form is focused.
-        if (event === 'input' && msie <= 11) return false;
+        if (event === 'input' && msie) return false;
 
         if (isUndefined(eventSupport[event])) {
           var divElm = document.createElement('div');

Diff for: src/ng/urlUtils.js

@@ -58,6 +58,7 @@ var originUrl = urlResolve(window.location.href);
 function urlResolve(url) {
   var href = url;
 
+  // Support: IE 9-11 only
   if (msie) {
     // Normalize before parse.  Refer Implementation Notes on why this is
     // done in two steps on IE.

Diff for: src/ngScenario/dsl.js

@@ -201,6 +201,13 @@ angular.scenario.dsl('binding', function() {
  */
 angular.scenario.dsl('input', function() {
   var chain = {};
+
+  // Support: IE 9-11 only
+  // 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.
+  // IE10+ implements 'input' event but it erroneously fires under various situations,
+  // e.g. when placeholder changes, or a form is focused.
   var supportInputEvent = 'oninput' in window.document.createElement('div') && !msie;
 
   chain.enter = function(value, event) {

Diff for: test/helpers/matchers.js

@@ -357,15 +357,19 @@ beforeEach(function() {
 
     toBeMarkedAsSelected: function() {
       // Selected is special because the element property and attribute reflect each other's state.
+
+      // Support: IE 9 only
       // IE9 will wrongly report hasAttribute('selected') === true when the property is
       // undefined or null, and the dev tools show that no attribute is set
+
       return {
         compare: function(actual) {
           var errors = [];
           if (actual.selected === null || typeof actual.selected === 'undefined' || actual.selected === false) {
             errors.push('Expected option property "selected" to be truthy');
           }
 
+          // Support: IE 9 only
           if (msie !== 9 && actual.hasAttribute('selected') === false) {
             errors.push('Expected option to have attribute "selected"');
           }
@@ -383,6 +387,7 @@ beforeEach(function() {
             errors.push('Expected option property "selected" to be falsy');
           }
 
+          // Support: IE 9 only
           if (msie !== 9 && actual.hasAttribute('selected')) {
             errors.push('Expected option not to have attribute "selected"');
           }

Diff for: test/ng/compileSpec.js

@@ -469,6 +469,10 @@ describe('$compile', function() {
       }));
 
       // NOTE: This test may be redundant.
+      // Support: Edge 14+
+      // An `<svg>` element inside a `<foreignObject>` element on MS Edge has no
+      // size, causing the included `<circle>` element to also have no size and thus fails an
+      // assertion (relying on the element having a non-zero size).
       if (!isEdge) {
         it('should handle custom svg containers that transclude to foreignObject' +
            ' that transclude to custom svg containers that transclude to custom elements', inject(function() {
@@ -1127,7 +1131,8 @@ describe('$compile', function() {
           expect(element).toHaveClass('class_2');
         }));
 
-        if (!msie || msie > 11) {
+        // Support: IE 9-11 only
+        if (!msie) {
           // style interpolation not working on IE (including IE11).
           it('should handle interpolated css style from replacing directive', inject(
             function($compile, $rootScope) {
@@ -10698,6 +10703,8 @@ describe('$compile', function() {
           expect(element.text()).toBe('102030');
           expect(newWatcherCount).toBe(3);
 
+          // Support: IE 11 only
+          // See #11781 and #14924
           if (msie === 11) {
             expect(element.find('ng-transclude').contents().length).toBe(1);
           }
@@ -10719,9 +10726,10 @@ describe('$compile', function() {
       expect(element.attr('src')).toEqual('http://example.com/image2.png');
     }));
 
+    // Support: IE 9 only
     // IE9 rejects the video / audio tag with "Error: Not implemented" and the source tag with
     // "Unable to get value of the property 'childNodes': object is null or undefined"
-    if (!msie || msie > 9) {
+    if (msie !== 9) {
       they('should NOT require trusted values for $prop src', ['video', 'audio'],
       function(tag) {
         inject(function($rootScope, $compile, $sce) {
@@ -11154,7 +11162,9 @@ describe('$compile', function() {
     }));
   });
 
-  if (!msie || msie >= 11) {
+  // Support: IE 9-10 only
+  // IEs <11 don't support srcdoc
+  if (!msie || msie === 11) {
     describe('iframe[srcdoc]', function() {
       it('should NOT set iframe contents for untrusted values', inject(function($compile, $rootScope, $sce) {
         element = $compile('<iframe srcdoc="{{html}}"></iframe>')($rootScope);

Diff for: test/ng/directive/booleanAttrsSpec.js

@@ -182,6 +182,7 @@ describe('ngSrc', function() {
   }));
 
 
+  // Support: IE 9-11 only
   if (msie) {
     it('should update the element property as well as the attribute', inject(
         function($compile, $rootScope, $sce) {
@@ -283,8 +284,9 @@ describe('ngHref', function() {
     expect(element.attr('href')).toEqual(undefined);
   }));
 
-  if (msie) {
-    // IE11/10/Edge fail when setting a href to a URL containing a % that isn't a valid escape sequence
+  // Support: IE 9-11 only, Edge 12-14+
+  if (msie || /\bEdge\/[\d\.]+\b/.test(window.navigator.userAgent)) {
+    // IE/Edge fail when setting a href to a URL containing a % that isn't a valid escape sequence
     // See https://github.com/angular/angular.js/issues/13388
     it('should throw error if ng-href contains a non-escaped percent symbol', inject(function($rootScope, $compile) {
       element = $compile('<a ng-href="http://www.google.com/{{\'a%link\'}}">')($rootScope);

Diff for: test/ng/directive/inputSpec.js

@@ -135,6 +135,7 @@ describe('input', function() {
 
 
   describe('IE placeholder input events', function() {
+    // Support: IE 9-11 only
     //IE fires an input event whenever a placeholder visually changes, essentially treating it as a value
     //Events:
     //  placeholder attribute change: *input*

Diff for: test/ng/locationSpec.js

@@ -39,8 +39,11 @@ describe('$location', function() {
     /* global urlParsingNode: true */
     var urlParsingNodePlaceholder;
 
-    beforeEach(inject(function($sniffer) {
-      if (msie) return;
+    beforeEach(function() {
+      // Support: non-Windows browsers
+      // These tests expect a Windows environment which we can only guarantee
+      // on IE & Edge.
+      if (msie || /\bEdge\/[\d\.]+\b/.test(window.navigator.userAgent)) return;
 
       urlParsingNodePlaceholder = urlParsingNode;
 
@@ -57,13 +60,14 @@ describe('$location', function() {
         search: '',
         setAttribute: angular.noop
       };
-    }));
+    });
 
-    afterEach(inject(function($sniffer) {
-      if (msie) return;
+    afterEach(function() {
+      // Support: non-Windows browsers
+      if (msie || /\bEdge\/[\d\.]+\b/.test(window.navigator.userAgent)) return;
       //reset urlParsingNode
       urlParsingNode = urlParsingNodePlaceholder;
-    }));
+    });
 
 
     it('should not include the drive name in path() on WIN', function() {

Diff for: test/ng/parseSpec.js

@@ -2180,8 +2180,9 @@ describe('parser', function() {
         expect(scope.$eval('getter()()')).toBe(33);
       });
 
+      // Support: IE 9 only
       // There is no "strict mode" in IE9
-      if (!msie || msie > 9) {
+      if (msie !== 9) {
         it('should set no context to functions returned by other functions', function() {
           scope.getter = function() { return function() { expect(this).toBeUndefined(); }; };
           scope.$eval('getter()()');

Diff for: test/ng/rootScopeSpec.js

@@ -13,9 +13,7 @@ describe('Scope', function() {
 
 
     it('should expose the constructor', inject(function($rootScope) {
-      if (msie < 11) return;
-      // eslint-disable-next-line no-proto
-      expect($rootScope.__proto__).toBe($rootScope.constructor.prototype);
+      expect(Object.getPrototypeOf($rootScope)).toBe($rootScope.constructor.prototype);
     }));
 
 
@@ -125,7 +123,9 @@ describe('Scope', function() {
       function Listener() {
         expect(this).toBeUndefined();
       }
-      if (msie < 10) return;
+      // Support: IE 9 only
+      // IE 9 doesn't support strict mode so its `this` will always be defined.
+      if (msie === 9) return;
       $rootScope.$watch(Getter, Listener);
       $rootScope.$digest();
     }));
@@ -1227,6 +1227,7 @@ describe('Scope', function() {
     }));
 
 
+    // Support: IE 9 only
     if (msie === 9) {
       // See issue https://github.com/angular/angular.js/issues/10706
       it('should completely disconnect all child scopes on IE9', inject(function($rootScope) {

Diff for: test/ng/snifferSpec.js

@@ -153,11 +153,12 @@ describe('$sniffer', function() {
 
 
     it('should claim that IE9 doesn\'t have support for "oninput"', function() {
+      // Support: IE 9-11 only
       // IE9 implementation is fubared, so it's better to pretend that it doesn't have the support
       // IE10+ implementation is fubared when mixed with placeholders
       mockDivElement = {oninput: noop};
 
-      expect($sniffer.hasEvent('input')).toBe(!(msie && msie <= 11));
+      expect($sniffer.hasEvent('input')).toBe(!msie);
     });
   });