fix($compile): properly clone attr.$observers in ng-repeat

The `attr` object was only shallow copied which caused all observers to be shared.
Fixing similar issue in ng-* boolean attributes as well as ng-src and ng-href.

src/ng/compiler.js

@@ -611,6 +611,7 @@ function $CompileProvider($provide) {
         } else {
           attrs = shallowCopy(templateAttrs);
           attrs.$element = jqLite(linkNode);
+          attrs.$observers = {};
         }
         element = attrs.$element;
 

src/ng/directive/booleanAttrDirs.js

@@ -283,9 +283,10 @@ forEach(BOOLEAN_ATTR, function(propName, attrName) {
   var normalized = directiveNormalize('ng-' + attrName);
   ngAttributeAliasDirectives[normalized] = function() {
     return {
+      priority: 100,
       compile: function(tpl, attr) {
-        attr.$observers[attrName] = [];
         return function(scope, element, attr) {
+          attr.$observers[attrName] = [];
           scope.$watch(attr[normalized], function(value) {
             attr.$set(attrName, value);
           });
@@ -301,9 +302,10 @@ forEach(['src', 'href'], function(attrName) {
   var normalized = directiveNormalize('ng-' + attrName);
   ngAttributeAliasDirectives[normalized] = function() {
     return {
+      priority: 100,
       compile: function(tpl, attr) {
-        attr.$observers[attrName] = [];
         return function(scope, element, attr) {
+          attr.$observers[attrName] = [];
           attr.$observe(normalized, function(value) {
             attr.$set(attrName, value);
           });

test/ng/compilerSpec.js

@@ -1374,6 +1374,41 @@ describe('$compile', function() {
     });
 
 
+    it('should properly $observe inside ng-repeat', function() {
+      var spies = [];
+
+      module(function($compileProvider) {
+        $compileProvider.directive('observer', function() {
+          return function(scope, elm, attr) {
+            spies.push(jasmine.createSpy('observer ' + spies.length));
+            attr.$observe('some', spies[spies.length - 1]);
+          };
+        });
+      });
+
+      inject(function($compile, $rootScope) {
+        element = $compile('<div><div ng-repeat="i in items">'+
+                              '<span some="id_{{i.id}}" observer></span>'+
+                           '</div></div>')($rootScope);
+
+        $rootScope.$apply(function() {
+          $rootScope.items = [{id: 1}, {id: 2}];
+        });
+
+        expect(spies[0]).toHaveBeenCalledOnceWith('id_1');
+        expect(spies[1]).toHaveBeenCalledOnceWith('id_2');
+        spies[0].reset();
+        spies[1].reset();
+
+        $rootScope.$apply(function() {
+          $rootScope.items[0].id = 5;
+        });
+
+        expect(spies[0]).toHaveBeenCalledOnceWith('id_5');
+      });
+    });
+
+
     describe('$set', function() {
       var attr;
       beforeEach(function(){