'ViewContext' interface extracted, files render workflow refactored to use this interface.

framework/yii/base/ViewContext.php

@@ -0,0 +1,30 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright (c) 2008 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\base;
+
+/**
+ * ViewContext represents possible context for the view rendering.
+ * It determines the way the non-global view files are searched.
+ * This interface introduces method [[findViewFile]], which will be used
+ * at [[View::render()]] to determine the file by view name, which does
+ * not match default format.
+ *
+ * @see View
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+interface ViewContext
+{
+	/**
+	 * Finds the view file based on the given view name.
+	 * @param string $view the view name.
+	 * @return string the view file path. Note that the file may not exist.
+	 */
+	public function findViewFile($view);
+}