[DevTools] Remove HelpScreen, turn SettingsScreen into dialog and web component.

third_party/WebKit/Source/devtools/front_end/ui/Dialog.js

Index: third_party/WebKit/Source/devtools/front_end/ui/Dialog.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui/Dialog.js b/third_party/WebKit/Source/devtools/front_end/ui/Dialog.js
index a93c4b00b24f2d0d460c79830e4c38957995bd9a..f54ae7a2a10b4d917e9e9c7cd21fd9d7d4f1f7de 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui/Dialog.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui/Dialog.js
@@ -53,18 +53,19 @@ WebInspector.Dialog = function()
  */
 WebInspector.Dialog.hasInstance = function()
 {
-    return !!WebInspector.Dialog._instance;
+    return !!WebInspector.Dialog._instances.length;
 }
 
+/** @type {!Array<!WebInspector.Dialog>} */
+WebInspector.Dialog._instances = [];
+
 WebInspector.Dialog.prototype = {
     /**
      * @override
      */
     show: function()
     {
-        if (WebInspector.Dialog._instance)
-            WebInspector.Dialog._instance.detach();
-        WebInspector.Dialog._instance = this;
+        WebInspector.Dialog._instances.push(this);
 
         this._glassPane = new WebInspector.GlassPane(/** @type {!Document} */ (WebInspector.Dialog._modalHostView.element.ownerDocument), this._dimmed);
         this._glassPane.element.addEventListener("click", this._onGlassPaneClick.bind(this), false);
@@ -87,7 +88,8 @@ WebInspector.Dialog.prototype = {
         this._glassPane.dispose();
         delete this._glassPane;
 
-        delete WebInspector.Dialog._instance;
+        console.assert(this === WebInspector.Dialog._instances.peekLast());

[yurys, 2015/10/13 00:52:11]

How can you be sure that the dialogs are not closed in different order?

[dgozman, 2015/10/13 01:57:42]

They are stacked on top of each other. The alternative is to close this one and
all others opened later. What do you prefer?

+        WebInspector.Dialog._instances.pop();
     },
 
     addCloseButton: function()
@@ -224,7 +226,7 @@ WebInspector.Dialog.modalHostView = function()
 
 WebInspector.Dialog.modalHostRepositioned = function()
 {
-    if (WebInspector.Dialog._instance)
-        WebInspector.Dialog._instance._position();
+    for (var index = 0; index < WebInspector.Dialog._instances.length; ++index)
+        WebInspector.Dialog._instances[index]._position();
 };