Add KtPsiFactory#createFileWithLightClassSupport

Allows to create light classes for KtFile built from text

compiler/frontend/src/org/jetbrains/kotlin/psi/KtPsiFactory.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2015 JetBrains s.r.o.
+ * Copyright 2010-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -188,6 +188,12 @@ class KtPsiFactory(private val project: Project) {
         return file
     }
 
+    fun createFileWithLightClassSupport(fileName: String, text: String, contextToAnalyzeIn: PsiElement): KtFile {
+        val file = createPhysicalFile(fileName, text)
+        file.analysisContext = contextToAnalyzeIn
+        return file
+    }
+
     fun createPhysicalFile(fileName: String, text: String): KtFile {
         return PsiFileFactory.getInstance(project).createFileFromText(fileName, KotlinFileType.INSTANCE, text, LocalTimeCounter.currentTime(), true) as KtFile
     }