DevTools: WI.SourceCodeDiff should not depend on UISourceCode

third_party/WebKit/Source/devtools/front_end/sources/SourceCodeDiff.js

Index: third_party/WebKit/Source/devtools/front_end/sources/SourceCodeDiff.js
diff --git a/third_party/WebKit/Source/devtools/front_end/sources/SourceCodeDiff.js b/third_party/WebKit/Source/devtools/front_end/sources/SourceCodeDiff.js
index 752d8c4de71961444f99fa0bf910a67888683f19..c282887164e19e0dbadcbc07cdf98335eb9d3554 100644
--- a/third_party/WebKit/Source/devtools/front_end/sources/SourceCodeDiff.js
+++ b/third_party/WebKit/Source/devtools/front_end/sources/SourceCodeDiff.js
@@ -4,16 +4,15 @@
 
 /**
  * @constructor
- * @param {!WebInspector.UISourceCode} uiSourceCode
+ * @param {!Promise<?string>} diffBaseline
  * @param {!WebInspector.CodeMirrorTextEditor} textEditor
  */
-WebInspector.SourceCodeDiff = function(uiSourceCode, textEditor)
+WebInspector.SourceCodeDiff = function(diffBaseline, textEditor)
 {
-    this._uiSourceCode = uiSourceCode;
     this._textEditor = textEditor;
     this._decorations = [];
     this._textEditor.installGutter(WebInspector.SourceCodeDiff.DiffGutterType, true);
-    this._diffBaseline = this._uiSourceCode.requestOriginalContent();
+    this._diffBaseline = diffBaseline;
     /** @type {!Array<!WebInspector.TextEditorPositionHandle>}*/
     this._animatedLines = [];
 }
@@ -193,8 +192,8 @@ WebInspector.SourceCodeDiff.prototype = {
      */
     _innerUpdate: function(baseline)
     {
-        var current = this._uiSourceCode.workingCopy();
-        if (typeof current !== "string" || typeof baseline !== "string") {
+        var current = this._textEditor.text();
+        if (typeof baseline !== "string") {
             this._updateDecorations(this._decorations, [] /* added */);
             this._decorations = [];
             return;