DevTools: Implement the console prompt with CodeMirror

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;
 }
 
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 }
 
 .CodeMirror-activeline .cm-trailing-whitespace {
     background-color: transparent;
 }
 
 .-theme-with-dark-background .CodeMirror .CodeMirror-selected {
     background-color: #454545;
 }
 
-.CodeMirror .auto-complete-text{
+.CodeMirror .auto-complete-text {
     color: rgb(128,128,128);
 }
+
+/** Prevent the codemirror textarea from stealing PageUp events **/
+.CodeMirror textarea {
+    resize: none;
+    overflow: hidden;
+}