javafx: accept imports in fx:root tags (IDEA-147975)

plugins/javaFX/javaFX-CE/testSrc/org/jetbrains/plugins/javaFX/fxml/JavaFXHighlightingTest.java

@@ -256,6 +256,10 @@ public class JavaFXHighlightingTest extends AbstractJavaFXTestCase {
     doTest();
   }
 
+  public void testRootTagWithImport() throws Exception {
+    doTest();
+  }
+
   public void testReadOnly() throws Exception {
     doTest();
   }

plugins/javaFX/src/org/jetbrains/plugins/javaFX/fxml/descriptors/JavaFxDefaultPropertyElementDescriptor.java

@@ -18,7 +18,6 @@ package org.jetbrains.plugins.javaFX.fxml.descriptors;
 import com.intellij.codeInsight.daemon.Validator;
 import com.intellij.openapi.project.Project;
 import com.intellij.psi.*;
-import com.intellij.psi.search.GlobalSearchScope;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.psi.util.PsiUtil;
 import com.intellij.psi.xml.XmlAttribute;
@@ -220,7 +219,7 @@ public class JavaFxDefaultPropertyElementDescriptor implements XmlElementDescrip
       if (typeAttr != null) {
         final String rootClassName = typeAttr.getValue();
         final Project project = context.getProject();
-        final PsiClass rootClass = rootClassName != null ? JavaPsiFacade.getInstance(project).findClass(rootClassName, GlobalSearchScope.allScope(project)) : null;
+        final PsiClass rootClass = rootClassName != null ?JavaFxPsiUtil.findPsiClass(rootClassName, context) : null;
         if (rootClass != null) {
           return new JavaFxClassBackedElementDescriptor(getName(), rootClass);
         }

plugins/javaFX/testData/highlighting/rootTagWithImport.fxml

@@ -0,0 +1,8 @@
+<?import javafx.scene.control.TextField?>
+<?import javafx.scene.control.Label?>
+<?import javafx.scene.layout.BorderPane?>
+
+<fx:root type = "BorderPane" minHeight="7" xmlns:fx="http://javafx.com/fxml">
+  <TextField fx:id="textField" text=""/>
+  <Label text="Hello"/>
+</fx:root>