DevTools: Fix visible whitespace for cm_modes

BUG=none

Review-Url: https://codereview.chromium.org/2385793003
Cr-Commit-Position: refs/heads/master@{#422928}

third_party/WebKit/LayoutTests/inspector/editor/php-highlighter.html

@@ -7,8 +7,7 @@ function test()
 {
     var mimeType = "text/x-php";
     var textEditor = InspectorTest.createTestEditor();
-    InspectorTest.addSniffer(textEditor, "_mimeTypeModesLoadedForTest", onModesLoaded);
-    textEditor.setMimeType(mimeType);
+    textEditor.setMimeType(mimeType).then(onModesLoaded);
 
     function onModesLoaded()
     {

third_party/WebKit/LayoutTests/inspector/editor/text-editor-token-at-position.html

@@ -35,10 +35,13 @@ function test()
         function testHighlightedText(next)
         {
             var textEditor = InspectorTest.createTestEditor();
-            textEditor.setMimeType("text/javascript");
-            textEditor.setText(text.join("\n"));
-            testTokenAtPosition(textEditor);
-            next();
+            textEditor.setMimeType("text/javascript").then(step1);
+            function step1()
+            {
+                textEditor.setText(text.join("\n"));
+                testTokenAtPosition(textEditor);
+                next();
+            }
         },
     ]);
 }

third_party/WebKit/Source/devtools/front_end/source_frame/SourcesTextEditor.js

@@ -485,11 +485,13 @@ WebInspector.SourcesTextEditor.prototype = {
     /**
      * @override
      * @param {string} mimeType
+     * @return {!Promise}
      */
     setMimeType: function(mimeType)
     {
         this._mimeType = mimeType;
-        WebInspector.CodeMirrorTextEditor.prototype.setMimeType.call(this, this._applyWhitespaceMimetype(mimeType));
+        return WebInspector.CodeMirrorTextEditor.prototype.setMimeType.call(this, mimeType)
+            .then(() => this._codeMirror.setOption("mode", this._applyWhitespaceMimetype(mimeType)));
     },
 
     _updateWhitespace: function()

third_party/WebKit/Source/devtools/front_end/text_editor/CodeMirrorTextEditor.js

@@ -698,27 +698,7 @@ WebInspector.CodeMirrorTextEditor.prototype = {
 
     /**
      * @param {string} mimeType
-     */
-    _updateCodeMirrorMode: function(mimeType)
-    {
-        this._codeMirror.setOption("mode", mimeType);
-        WebInspector.CodeMirrorTextEditor._loadMimeTypeModes(mimeType, innerUpdateCodeMirrorMode.bind(this));
-
-        /**
-         * @this WebInspector.CodeMirrorTextEditor
-         */
-        function innerUpdateCodeMirrorMode()
-        {
-            this._mimeTypeModesLoadedForTest();
-            this._updateCodeMirrorMode(mimeType);
-        }
-    },
-
-    // Do not remove, this function is sniffed in tests.
-    _mimeTypeModesLoadedForTest: function() { },
-
-    /**
-     * @param {string} mimeType
+     * @return {!Promise}
      */
     setMimeType: function(mimeType)
     {
@@ -726,7 +706,7 @@ WebInspector.CodeMirrorTextEditor.prototype = {
             this._enableLongLinesMode();
         else
             this._disableLongLinesMode();
-        this._updateCodeMirrorMode(mimeType);
+        return WebInspector.CodeMirrorTextEditor._loadMimeTypeModes(mimeType).then(() => this._codeMirror.setOption("mode", mimeType));
     },
 
     /**
@@ -1621,9 +1601,9 @@ WebInspector.CodeMirrorTextEditor._loadedMimeModeExtensions = new Set();
 
 /**
  * @param {string} mimeType
- * @param {function()} callback
+ * @return {!Promise}
  */
-WebInspector.CodeMirrorTextEditor._loadMimeTypeModes = function(mimeType, callback)
+WebInspector.CodeMirrorTextEditor._loadMimeTypeModes = function(mimeType)
 {
     var installed = WebInspector.CodeMirrorTextEditor._loadedMimeModeExtensions;
 
@@ -1650,8 +1630,7 @@ WebInspector.CodeMirrorTextEditor._loadMimeTypeModes = function(mimeType, callba
     var promises = [];
     for (var extension of modesToLoad)
         promises.push(extension.instance().then(installMode.bind(null, extension)));
-    if (promises.length)
-        Promise.all(promises).then(callback);
+    return Promise.all(promises);
 
     /**
      * @param {!Runtime.Extension} extension