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

Source/devtools/front_end/inspector.css

Index: Source/devtools/front_end/inspector.css
diff --git a/Source/devtools/front_end/inspector.css b/Source/devtools/front_end/inspector.css
index e86d4b853afd23a024c561547ae0444d5f6763ac..7c908318ffa7d802c441f5bd9ce4f89c2cb3985b 100644
--- a/Source/devtools/front_end/inspector.css
+++ b/Source/devtools/front_end/inspector.css
@@ -2800,3 +2800,11 @@ body.platform-mac .progress-bar-container progress {
 body.undocked .toolbar-close-button-item {
     display: none;
 }
+
+body.dock-to-bottom #inspector-split-view .split-view-resizer {
+    border-top: 1px solid rgb(64%, 64%, 64%);
+}
+
+body.dock-to-right #inspector-split-view .split-view-resizer {
+    border-left: 1px solid rgb(64%, 64%, 64%);
+}