Refactor edit textarea into gr-default-editor

Done to keep with the event-based pattern of keeping track of edits, as
opposed to the existing mechanism of two-way databinding.

Bug: Issue 4437
Change-Id: Iec35538d9d163a983ecd405e4cd52ab5a41d7772

polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.html

diff --git a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.html b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.html
index 3042e76..1dade20 100644
--- a/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.html
+++ b/polygerrit-ui/app/elements/edit/gr-editor-view/gr-editor-view.html
@@ -26,9 +26,9 @@
 <link rel="import" href="../../shared/gr-editable-label/gr-editable-label.html">
 <link rel="import" href="../../shared/gr-fixed-panel/gr-fixed-panel.html">
 <link rel="import" href="../../shared/gr-rest-api-interface/gr-rest-api-interface.html">
+<link rel="import" href="../gr-default-editor/gr-default-editor.html">
 <link rel="import" href="../../../styles/shared-styles.html">
 
-
 <dom-module id="gr-editor-view">
   <template>
     <style include="shared-styles">
@@ -54,19 +54,6 @@
       .textareaWrapper {
         margin: var(--default-horizontal-margin);
       }
-      .textareaWrapper textarea {
-        border: 1px solid #ddd;
-        border-radius: 3px;
-        box-sizing: border-box;
-        font-family: var(--monospace-font-family);
-        min-height: 60vh;
-        resize: none;
-        white-space: pre;
-        width: 100%;
-      }
-      .textareaWrapper textarea:focus {
-        outline: none;
-      }
       .textareaWrapper .editButtons {
         display: none;
       }
@@ -100,7 +87,7 @@
         <gr-endpoint-param name="fileContent" value="[[_newContent]]"></gr-endpoint-param>
         <gr-endpoint-param name="prefs" value="[[_prefs]]"></gr-endpoint-param>
         <gr-endpoint-param name="fileType" value="[[_type]]"></gr-endpoint-param>
-        <textarea value="{{_newContent::input}}" id="file"></textarea>
+        <gr-default-editor id="file" file-content="[[_newContent]]"></gr-default-editor>
       </gr-endpoint-decorator>
     </div>
     <gr-rest-api-interface id="restAPI"></gr-rest-api-interface>