Add spec-compliant properties and methods to .NET IWebElement

The W3C WebDriver Specification defines additional commands for web
elements. This commit introduces properties and methods for execution of
those commands in the .NET language bindings. The added items on
IWebElement are:

* ComputedAccessibleLabel property: Allows the user to get the result of
  the accessible name and description computation for the accessible
  name of the element.
* ComputedAccessibleRole property: Allows the user to get the result of
  the computation of the ARIA role for this element. Note that this
  property is subject to change its return type, as the specification
  needs clarification as to the return type.
* GetDomProperty method: Allows the user to get the value of an
  IDL-defined property of the element. These properties are usually
  accessed via JavaScript. This method replaces the GetProperty method,
  which is now marked as obsolete, as it is being renamed to
  GetDomProperty for consistency in the Selenium API.
* GetDomAttribute method: Allows the user to get the value of an
  attribute declared in the HTML markup of the element. This differs
  from the GetAttribute method, in that it _only_ returns declared
  attributes, whereas the GetAttribute method will return one of either
  a declared attribute or an IDL property of the element, without
  distinction between the two.

Author: jimevans

dotnet/src/webdriver/Remote/DriverCommand.cs

@@ -273,6 +273,16 @@ public static class DriverCommand
         /// </summary>
         public static readonly string GetElementValueOfCssProperty = "getElementValueOfCssProperty";
 
+        /// <summary>
+        /// Represents GetComputedAccessibleLabel command
+        /// </summary>
+        public static readonly string GetComputedAccessibleLabel = "getComputedAccessibleLabel";
+
+        /// <summary>
+        /// Represents GetComputedAccessibleRole command
+        /// </summary>
+        public static readonly string GetComputedAccessibleRole = "getComputedAccessibleRole";
+
         /// <summary>
         /// Represents ElementEquals command
         /// </summary>

dotnet/src/webdriver/Remote/RemoteWebElement.cs

@@ -217,6 +217,38 @@ public virtual Point LocationOnScreenOnceScrolledIntoView
             }
         }
 
+        /// <summary>
+        /// Gets the computed accessible label of this element.
+        /// </summary>
+        public virtual string ComputedAccessibleLabel
+        {
+            get
+            {
+                Dictionary<string, object> parameters = new Dictionary<string, object>();
+                parameters.Add("id", this.Id);
+                Response commandResponse = this.Execute(DriverCommand.GetComputedAccessibleLabel, parameters);
+                return commandResponse.Value.ToString();
+            }
+        }
+
+        /// <summary>
+        /// Gets the computed ARIA role for this element.
+        /// </summary>
+        public virtual string ComputedAccessibleRole
+        {
+            get
+            {
+                // TODO: Returning this as a string is incorrect. The W3C WebDriver Specification
+                // needs to be updated to more throughly document the structure of what is returned
+                // by this command. Once that is done, a type-safe class will be created, and will
+                // be returned by this property.
+                Dictionary<string, object> parameters = new Dictionary<string, object>();
+                parameters.Add("id", this.Id);
+                Response commandResponse = this.Execute(DriverCommand.GetComputedAccessibleRole, parameters);
+                return commandResponse.Value.ToString();
+            }
+        }
+
         /// <summary>
         /// Gets the coordinates identifying the location of this element using
         /// various frames of reference.
@@ -353,15 +385,15 @@ public virtual void Click()
         }
 
         /// <summary>
-        /// Gets the value of the specified attribute for this element.
+        /// Gets the value of the specified attribute or property for this element.
         /// </summary>
-        /// <param name="attributeName">The name of the attribute.</param>
-        /// <returns>The attribute's current value. Returns a <see langword="null"/> if the
-        /// value is not set.</returns>
+        /// <param name="attributeName">The name of the attribute or property.</param>
+        /// <returns>The attribute's or property's current value. Returns a <see langword="null"/>
+        /// if the value is not set.</returns>
         /// <remarks>The <see cref="GetAttribute"/> method will return the current value
-        /// of the attribute, even if the value has been modified after the page has been
-        /// loaded. Note that the value of the following attributes will be returned even if
-        /// there is no explicit attribute on the element:
+        /// of the attribute or property, even if the value has been modified after the page
+        /// has been loaded. Note that the value of the following attributes will be returned
+        /// even if there is no explicit attribute on the element:
         /// <list type="table">
         /// <listheader>
         /// <term>Attribute name</term>
@@ -384,6 +416,9 @@ public virtual void Click()
         /// <description>Input and other UI elements</description>
         /// </item>
         /// </list>
+        /// The method looks both in declared attributes in the HTML markup of the page, and
+        /// in the properties of the elemnt as found when accessing the element's properties
+        /// via JavaScript.
         /// </remarks>
         /// <exception cref="StaleElementReferenceException">Thrown when the target element is no longer valid in the document DOM.</exception>
         public virtual string GetAttribute(string attributeName)
@@ -414,14 +449,60 @@ public virtual string GetAttribute(string attributeName)
             return attributeValue;
         }
 
+        /// <summary>
+        /// Gets the value of a declared HTML attribute of this element.
+        /// </summary>
+        /// <param name="attributeName">The name of the HTML attribugte to get the value of.</param>
+        /// <returns>The HTML attribute's current value. Returns a <see langword="null"/> if the
+        /// value is not set or the declared attribute does not exist.</returns>
+        /// <exception cref="StaleElementReferenceException">Thrown when the target element is no longer valid in the document DOM.</exception>
+        /// <remarks>
+        /// As opposed to the <see cref="GetAttribute(string)"/> method, this method
+        /// only returns attriibutes decalred in the element's HTML markup. To access the value
+        /// of an IDL property of the element, either use the <see cref="GetAttribute(string)"/>
+        /// method or the <see cref="GetDomProperty(string)"/> method.
+        /// </remarks>
+        public virtual string GetDomAttribute(string attributeName)
+        {
+            string attributeValue = string.Empty;
+            Dictionary<string, object> parameters = new Dictionary<string, object>();
+            parameters.Add("id", this.Id);
+            parameters.Add("name", attributeName);
+
+            Response commandResponse = this.Execute(DriverCommand.GetElementAttribute, parameters);
+            if (commandResponse.Value == null)
+            {
+                attributeValue = null;
+            }
+            else
+            {
+                attributeValue = commandResponse.Value.ToString();
+            }
+
+            return attributeValue;
+        }
+
         /// <summary>
         /// Gets the value of a JavaScript property of this element.
         /// </summary>
-        /// <param name="propertyName">The name JavaScript the JavaScript property to get the value of.</param>
+        /// <param name="propertyName">The name of the JavaScript property to get the value of.</param>
         /// <returns>The JavaScript property's current value. Returns a <see langword="null"/> if the
         /// value is not set or the property does not exist.</returns>
         /// <exception cref="StaleElementReferenceException">Thrown when the target element is no longer valid in the document DOM.</exception>
+        [Obsolete("Use the GetDomProperty method instead.")]
         public virtual string GetProperty(string propertyName)
+        {
+            return this.GetDomProperty(propertyName);
+        }
+
+        /// <summary>
+        /// Gets the value of a JavaScript property of this element.
+        /// </summary>
+        /// <param name="propertyName">The name of the JavaScript property to get the value of.</param>
+        /// <returns>The JavaScript property's current value. Returns a <see langword="null"/> if the
+        /// value is not set or the property does not exist.</returns>
+        /// <exception cref="StaleElementReferenceException">Thrown when the target element is no longer valid in the document DOM.</exception>
+        public virtual string GetDomProperty(string propertyName)
         {
             string propertyValue = string.Empty;
             Dictionary<string, object> parameters = new Dictionary<string, object>();

dotnet/src/webdriver/Remote/W3CWireProtocolCommandInfoRepository.cs

@@ -84,6 +84,8 @@ protected override void InitializeCommandDictionary()
             this.TryAddCommand(DriverCommand.GetElementAttribute, new CommandInfo(CommandInfo.GetCommand, "/session/{sessionId}/element/{id}/attribute/{name}"));
             this.TryAddCommand(DriverCommand.GetElementProperty, new CommandInfo(CommandInfo.GetCommand, "/session/{sessionId}/element/{id}/property/{name}"));
             this.TryAddCommand(DriverCommand.GetElementValueOfCssProperty, new CommandInfo(CommandInfo.GetCommand, "/session/{sessionId}/element/{id}/css/{name}"));
+            this.TryAddCommand(DriverCommand.GetComputedAccessibleLabel, new CommandInfo(CommandInfo.GetCommand, "/session/{sessionId}/element/{id}/computedlabel"));
+            this.TryAddCommand(DriverCommand.GetComputedAccessibleRole, new CommandInfo(CommandInfo.GetCommand, "/session/{sessionId}/element/{id}/computedrole"));
             this.TryAddCommand(DriverCommand.GetElementText, new CommandInfo(CommandInfo.GetCommand, "/session/{sessionId}/element/{id}/text"));
             this.TryAddCommand(DriverCommand.GetElementTagName, new CommandInfo(CommandInfo.GetCommand, "/session/{sessionId}/element/{id}/name"));
             this.TryAddCommand(DriverCommand.GetElementRect, new CommandInfo(CommandInfo.GetCommand, "/session/{sessionId}/element/{id}/rect"));