DevTools: tint the glass pane when modal dialog is being shown

BUG=527611

Review URL: https://codereview.chromium.org/1327903003

git-svn-id: svn://svn.chromium.org/blink/trunk@201689 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/devtools/front_end/dialog.css

@@ -48,3 +48,6 @@
     outline: none;
 }
 
+#glass-pane.tinted {
+    background-color: rgba(0, 0, 0, 0.2) !important;
+}

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

@@ -46,6 +46,8 @@ WebInspector.Dialog = function(relativeToElement, delegate, modal)
     // Install glass pane capturing events.
     this._glassPane.element.tabIndex = 0;
     this._glassPane.element.addEventListener("focus", this._onGlassPaneFocus.bind(this), false);
+    if (this._modal)
+        this._glassPane.element.classList.add("tinted");
 
     this._element = this._glassPane.element.createChild("div");
     this._element.tabIndex = 0;