[DevTools] Prepare to move Popover to shadow DOM.

third_party/WebKit/Source/devtools/front_end/text_editor/cmdevtools.css

 .CodeMirror {
     line-height: 1.2em !important;
     background-color: transparent !important;
     color: #222;
 }
 
 .CodeMirror-linewidget {
     overflow: visible !important;
 }
 
@@ skipping 350 matching lines @@
     padding-left: 5px;
     color: #222;
     -webkit-user-select: text;
 }
 
 .CodeMirror .cm-execution-line .text-editor-value-decoration {
     background-color: transparent;
     opacity: 0.5;
 }
 
-.text-editor-messages-description-container {
-    display: inline-block;
-}
-
-.text-editor-row-message:first-child {
-    border-top-width: 0;
-}
-
-.text-editor-row-message {
-    border-top: 1px solid rgb(215, 215, 215);
-    line-height: 1.2;
-    white-space: nowrap;
-    display: flex;
-    align-items: center;
-    justify-content: flex-start;
-}
-
-.text-editor-row-message .message-repeat-count {
-    margin-right: 0.5em;
-}
-
 .CodeMirror .text-editor-line-decoration-icon {
     position: absolute;
     cursor: pointer;
     right: -16px;
     top: -9px;
 }
 
 .CodeMirror .text-editor-line-with-warning:not(.cm-execution-line):not(.cm-readonly-highlight) {
     background-color: rgba(241, 230, 0, 0.1);
 }
@@ skipping 37 matching lines @@
 
 .CodeMirror .auto-complete-text {
     color: rgb(128,128,128);
 }
 
 /** Prevent the codemirror textarea from stealing PageUp events **/
 .CodeMirror textarea {
     resize: none;
     overflow: hidden;
 }