DevTools: remove unused CSS.

Source/devtools/front_end/responsiveDesignView.css

Index: Source/devtools/front_end/responsiveDesignView.css
diff --git a/Source/devtools/front_end/responsiveDesignView.css b/Source/devtools/front_end/responsiveDesignView.css
index ffe606efc1cb77e44feeeeac522027b67242cadb..7ebc5e0ce86136bdf1c0423262a478285dbe2260 100644
--- a/Source/devtools/front_end/responsiveDesignView.css
+++ b/Source/devtools/front_end/responsiveDesignView.css
@@ -439,14 +439,6 @@
     flex: none;
 }
 
-.responsive-design-ruler-glasspane {
-    position: absolute;
-    left: 0;
-    right: 0;
-    top: 0;
-    background-color: transparent;
-}
-
 .responsive-design-toggle-media-inspector .glyph {
     background-color: rgb(180, 180, 180);
     -webkit-mask-position: -128px -48px;
@@ -563,29 +555,3 @@
 .media-inspector-label-left {
     left: 2px;
 }
-
-/* Media query serifs on ruler */
-
-.media-inspector-threshold {
-    position: absolute;
-    top: 0px;
-    bottom: 0px;
-    width: 5px;
-    margin-left: -2px;
-}
-
-.media-inspector-threshold::before {
-    content: ".";
-    color: transparent;
-    position: absolute;
-    left: 2px;
-    right: 2px;
-    top: 0px;
-    bottom: 0px;
-    box-sizing: border-box;
-    border-left: 1px solid rgb(204, 104, 31);
-}
-
-.media-inspector-threshold:hover {
-    background-color: rgb(204, 104, 31);
-}