DevTools: "Jump between editing locations" experiment

Source/devtools/front_end/CodeMirrorTextEditor.js

Index: Source/devtools/front_end/CodeMirrorTextEditor.js
diff --git a/Source/devtools/front_end/CodeMirrorTextEditor.js b/Source/devtools/front_end/CodeMirrorTextEditor.js
index e9787da944752e9dabec500b6d65031d656bf565..fbb3c227303d99cdfe753786d8ff14d49884bb1d 100644
--- a/Source/devtools/front_end/CodeMirrorTextEditor.js
+++ b/Source/devtools/front_end/CodeMirrorTextEditor.js
@@ -148,10 +148,17 @@ WebInspector.CodeMirrorTextEditor = function(url, delegate)
     this._codeMirror.on("beforeChange", this._beforeChange.bind(this));
     this._codeMirror.on("gutterClick", this._gutterClick.bind(this));
     this._codeMirror.on("cursorActivity", this._cursorActivity.bind(this));
+    this._codeMirror.on("beforeSelectionChange", this._beforeSelectionChange.bind(this));
     this._codeMirror.on("scroll", this._scroll.bind(this));
     this._codeMirror.on("focus", this._focus.bind(this));
     this._codeMirror.on("blur", this._blur.bind(this));
     this.element.addEventListener("contextmenu", this._contextMenu.bind(this), false);
+    this.element.addEventListener("mousedown", function() {
+        this._anticipateJump = true;
+    }.bind(this), true);
+    this.element.addEventListener("mousedown", function() {
+        delete this._anticipateJump;
+    }.bind(this), false);
 
     this.element.addStyleClass("fill");
     this.element.style.overflow = "hidden";
@@ -220,9 +227,15 @@ WebInspector.CodeMirrorTextEditor.LongLineModeLineLengthThreshold = 2000;
 WebInspector.CodeMirrorTextEditor.MaximumNumberOfWhitespacesPerSingleSpan = 16;
 
 WebInspector.CodeMirrorTextEditor.prototype = {
+    willHide: function()
+    {
+        this._reportJump(this._codeMirror.getCursor("head"), null);
+    },
+
     wasShown: function()
     {
         this._codeMirror.refresh();
+        this._reportJump(null, this._codeMirror.getCursor("head"));
     },
 
     _guessIndentationLevel: function()
@@ -780,8 +793,11 @@ WebInspector.CodeMirrorTextEditor.prototype = {
         this.revealLine(lineNumber);
         this._codeMirror.addLineClass(this._highlightedLine, null, "cm-highlight");
         this._clearHighlightTimeout = setTimeout(this.clearPositionHighlight.bind(this), 2000);
-        if (!this.readOnly())
-            this._codeMirror.setSelection(new CodeMirror.Pos(lineNumber, columnNumber));
+        if (!this.readOnly()) {
+            this._anticipateJump = true;
+            this.setSelection(WebInspector.TextRange.createFromLocation(lineNumber, columnNumber));
+            delete this._anticipateJump;
+        }
     },
 
     clearPositionHighlight: function()
@@ -970,6 +986,30 @@ WebInspector.CodeMirrorTextEditor.prototype = {
             this._codeMirror.operation(this._tokenHighlighter.highlightSelectedTokens.bind(this._tokenHighlighter));
     },
 
+    /**
+     * @param {CodeMirror} codeMirror
+     * @param {{head: CodeMirror.Pos, anchor: CodeMirror.Pos}} selection
+     */
+    _beforeSelectionChange: function(codeMirror, selection)
+    {
+        if (!this._anticipateJump)
+            return;
+        this._reportJump(codeMirror.getCursor("head"), selection.head)
+    },
+
+    /**
+     * @param {?CodeMirror.Pos} from
+     * @param {?CodeMirror.Pos} to
+     */
+    _reportJump: function(from, to)
+    {
+        if (from && to && from.line === to.line && from.ch === to.ch)
+            return;
+        var fromHandle = from ? new WebInspector.CodeMirrorTextEditor.TextEditorPositionHandler(this._codeMirror, from) : null;
+        var toHandle = to ? new WebInspector.CodeMirrorTextEditor.TextEditorPositionHandler(this._codeMirror, to) : null;
+        this._delegate.onJumpToPosition(fromHandle, toHandle);
+    },
+
     _scroll: function()
     {
         if (this._scrollTimer)
@@ -1165,6 +1205,45 @@ WebInspector.CodeMirrorTextEditor.prototype = {
 
 /**
  * @constructor
+ * @implements {WebInspector.TextEditorPositionHandler}
+ * @param {CodeMirror} codeMirror
+ * @param {CodeMirror.Pos} pos
+ */
+WebInspector.CodeMirrorTextEditor.TextEditorPositionHandler = function(codeMirror, pos)
+{
+    this._codeMirror = codeMirror;
+    this._lineHandle = codeMirror.getLineHandle(pos.line);
+    this._columnNumber = pos.ch;
+}
+
+WebInspector.CodeMirrorTextEditor.TextEditorPositionHandler.prototype = {
+    /**
+     * @return {?{lineNumber: number, columnNumber: number}}
+     */
+    resolve: function()
+    {
+        var lineNumber = this._codeMirror.getLineNumber(this._lineHandle);
+        if (typeof lineNumber !== "number")
+            return null;
+        return {
+            lineNumber: lineNumber,
+            columnNumber: this._columnNumber
+        };
+    },
+
+    /**
+     * @param {WebInspector.TextEditorPositionHandler} positionHandle
+     * @return {boolean}
+     */
+    equal: function(positionHandle)
+    {
+        return positionHandle._lineHandle === this._lineHandle && positionHandle._columnNumber == this._columnNumber &&
+            positionHandle._codeMirror === this._codeMirror;
+    }
+}
+
+/**
+ * @constructor
  * @param {CodeMirror} codeMirror
  */
 WebInspector.CodeMirrorTextEditor.TokenHighlighter = function(codeMirror)