DevTools: Migrate from -webkit-user-modify to contenteditable

third_party/WebKit/Source/devtools/front_end/ui/textPrompt.css

Index: third_party/WebKit/Source/devtools/front_end/ui/textPrompt.css
diff --git a/third_party/WebKit/Source/devtools/front_end/ui/textPrompt.css b/third_party/WebKit/Source/devtools/front_end/ui/textPrompt.css
index 76335a533ca75bea7582cb1b77e10df4ac836fb6..9cb04edc076eeeef2f6be148c2a8b1187ec22135 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui/textPrompt.css
+++ b/third_party/WebKit/Source/devtools/front_end/ui/textPrompt.css
@@ -10,12 +10,10 @@
 }
 
 .text-prompt-editing {
-    -webkit-user-select: text;
     box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.2),
                 0 2px 4px rgba(0, 0, 0, 0.2),
                 0 2px 6px rgba(0, 0, 0, 0.1);
     background-color: white;
-    -webkit-user-modify: read-write-plaintext-only;
     text-overflow: clip !important;
     padding-left: 2px;
     margin-left: -2px;
@@ -30,14 +28,11 @@
 .text-prompt-editing ::content * {
     color: #222 !important;
     text-decoration: none !important;
-    -webkit-user-modify: read-write-plaintext-only;
     white-space: pre;
 }
 
 ::content .auto-complete-text {
     color: rgb(128, 128, 128) !important;
-    -webkit-user-select: none;
-    -webkit-user-modify: read-only;
 }
 
 ::content .text-prompt[data-placeholder]:empty::before {