fix(debounce): fix argument slicing

Closes #4859
Closes #4860

Author: Astashenkau

src/debounce/debounce.js

@@ -8,7 +8,7 @@ angular.module('ui.bootstrap.debounce', [])
 
       return function() {
         var self = this;
-        var args = Array.prototype.slice(arguments);
+        var args = Array.prototype.slice.call(arguments);
         if (timeoutPromise) {
           $timeout.cancel(timeoutPromise);
         }
@@ -18,4 +18,4 @@ angular.module('ui.bootstrap.debounce', [])
         }, debounceTime);
       };
     };
-  }]);
+  }]);

src/debounce/test/debounce.spec.js

@@ -1,12 +1,13 @@
 describe('$$debounce', function() {
-  var $$debounce, $timeout, debouncedFunction, i;
+  var $$debounce, $timeout, debouncedFunction, i, args;
 
   beforeEach(module('ui.bootstrap.debounce'));
   beforeEach(inject(function(_$$debounce_, _$timeout_) {
     $$debounce = _$$debounce_;
     $timeout = _$timeout_;
     i = 0;
     debouncedFunction = $$debounce(function() {
+      args = Array.prototype.slice.call(arguments);
       i++;
     }, 100);
   }));
@@ -37,4 +38,11 @@ describe('$$debounce', function() {
 
     expect(i).toBe(1);
   });
+
+  it('should properly pass arguments to debounced function', function() {
+    debouncedFunction(1, 2, 3);
+    $timeout.flush(100);
+
+    expect(args).toEqual([1, 2, 3]);
+  });
 });