Devtools[LayoutEditor]: Rework layout-editor workflow

Source/devtools/front_end/components/InspectElementModeController.js

Index: Source/devtools/front_end/components/InspectElementModeController.js
diff --git a/Source/devtools/front_end/components/InspectElementModeController.js b/Source/devtools/front_end/components/InspectElementModeController.js
index 87ef22f29ca9906747d771339adc647aae8ef8f3..4c953cdd56d1315f62f3c12cd45f72a3d5db6d89 100644
--- a/Source/devtools/front_end/components/InspectElementModeController.js
+++ b/Source/devtools/front_end/components/InspectElementModeController.js
@@ -55,10 +55,10 @@ WebInspector.InspectElementModeController.prototype = {
     {
         // When DevTools are opening in the inspect element mode, the first target comes in
         // much later than the InspectorFrontendAPI.enterInspectElementMode event.
-        if (!this.enabled())
+        if (!this.started())
             return;
         var domModel = WebInspector.DOMModel.fromTarget(target);
-        domModel.setInspectModeEnabled(true, WebInspector.moduleSetting("showUAShadowDOM").get());
+        domModel.setInspectModeEnabled(true, WebInspector.moduleSetting("showUAShadowDOM").get() ? "showUAShadowDOM" : null);
     },
 
     /**
@@ -72,24 +72,35 @@ WebInspector.InspectElementModeController.prototype = {
     /**
      * @return {boolean}
      */
-    enabled: function()
+    started: function()
     {
         return this._toggleSearchButton.toggled();
     },
 
-    disable: function()
+    stop: function()
     {
-        if (this.enabled())
+        if (this.started())
             this._toggleSearch();
     },
 
+    disable: function()
+    {
+        this.stop();
+        this._toggleSearchButton.setEnabled(false);
+    },
+
+    enable: function()
+    {
+        this._toggleSearchButton.setEnabled(true);
+    },
+
     _toggleSearch: function()
     {
-        var enabled = !this.enabled();
+        var enabled = !this.started();
         this._toggleSearchButton.setToggled(enabled);
 
         for (var domModel of WebInspector.DOMModel.instances())
-            domModel.setInspectModeEnabled(enabled, WebInspector.moduleSetting("showUAShadowDOM").get());
+            domModel.setInspectModeEnabled(enabled, WebInspector.moduleSetting("showUAShadowDOM").get() ? "showUAShadowDOM" : null);
     },
 
     _suspendStateChanged: function()