DevTools: Add JSDoc for static methods, fix JSDoc types and induced errors

Source/devtools/front_end/ScreencastView.js

Index: Source/devtools/front_end/ScreencastView.js
diff --git a/Source/devtools/front_end/ScreencastView.js b/Source/devtools/front_end/ScreencastView.js
index 7a10a5a352037bec3203a1b4c4f74812e36d50d7..cc5724da6fa00580b793f1073ca08e02ffc8fc27 100644
--- a/Source/devtools/front_end/ScreencastView.js
+++ b/Source/devtools/front_end/ScreencastView.js
@@ -249,7 +249,7 @@ WebInspector.ScreencastView.prototype = {
     },
 
     /**
-     * @param {!Event} event
+     * @param {?Event} event
      */
     _handleMouseEvent: function(event)
     {
@@ -288,7 +288,7 @@ WebInspector.ScreencastView.prototype = {
     },
 
     /**
-     * @param {!KeyboardEvent} event
+     * @param {?Event} event
      */
     _handleKeyEvent: function(event)
     {
@@ -297,7 +297,7 @@ WebInspector.ScreencastView.prototype = {
             return;
         }
 
-        var shortcutKey = WebInspector.KeyboardShortcut.makeKeyFromEvent(event);
+        var shortcutKey = WebInspector.KeyboardShortcut.makeKeyFromEvent(/** @type {!KeyboardEvent} */ (event));
         var handler = this._shortcuts[shortcutKey];
         if (handler && handler(event)) {
             event.consume();
@@ -320,7 +320,7 @@ WebInspector.ScreencastView.prototype = {
     },
 
     /**
-     * @param {!Event} event
+     * @param {?Event} event
      */
     _handleContextMenuEvent: function(event)
     {
@@ -328,7 +328,7 @@ WebInspector.ScreencastView.prototype = {
     },
 
     /**
-     * @param {!Event} event
+     * @param {?Event} event
      */
     _simulateTouchGestureForMouseEvent: function(event)
     {
@@ -489,7 +489,7 @@ WebInspector.ScreencastView.prototype = {
     },
 
     /**
-     * @param {!Event} event
+     * @param {?Event} event
      * @return {!{x: number, y: number}}
      */
     _zoomIntoScreenSpace: function(event)
@@ -502,7 +502,7 @@ WebInspector.ScreencastView.prototype = {
     },
 
     /**
-     * @param {!Event} event
+     * @param {?Event} event
      * @return {!{x: number, y: number}}
      */
     _convertIntoScreenSpace: function(event)
@@ -513,7 +513,7 @@ WebInspector.ScreencastView.prototype = {
     },
 
     /**
-     * @param {!Event} event
+     * @param {?Event} event
      * @return {number}
      */
     _modifiersForEvent: function(event)
@@ -943,7 +943,7 @@ WebInspector.ScreencastView.prototype = {
 }
 
 /**
- * @param {!HTMLElement} element
+ * @param {!Element} element
  * @constructor
  */
 WebInspector.ScreencastView.ProgressTracker = function(element) {