DevTools: added "overlayContents" mode, where DevTools content is placed around and underneath inse…

Source/devtools/front_end/inspectorCommon.css

 html {
     height: 100%;
 }
 
 body {
     cursor: default;
     position: absolute;
     top: 0;
     bottom: 0;
     left: 0;
@@ skipping 10 matching lines @@
 body.platform-linux {
   color: rgb(48, 57, 66);
   font-family: Ubuntu, Arial, sans-serif;
 }
 
 body.platform-mac {
   color: rgb(48, 57, 66);
   font-family: 'Lucida Grande', sans-serif;
 }
 
+body.dock-to-right:not(.undocked):not(.overlay-contents) {
+    border-left: 1px solid rgb(80, 80, 80);
+}
+
+body.dock-to-right.inactive:not(.undocked):not(.overlay-contents) {
+    border-left: 1px solid rgb(64%, 64%, 64%);
+}
+
 body.platform-windows {
   font-family: 'Segoe UI', Tahoma, sans-serif;
 }
 
-body.dock-to-right:not(.undocked) {
-    border-left: 1px solid rgb(80, 80, 80);
-}
-
-body.dock-to-right.inactive:not(.undocked) {
-    border-left: 1px solid rgb(64%, 64%, 64%);
-}
-
 * {
     box-sizing: border-box;
 }
 
 :focus {
     outline: none;
 }
 
 img {
     -webkit-user-drag: none;
@@ skipping 191 matching lines @@
     white-space: nowrap;
     text-overflow: ellipsis;
     overflow: hidden;
     line-height: 16px;
 }
 
 .sidebar-label {
     font-size: 11px;
 }