Fix saving modified skp from debugger

https://codereview.appspot.com/7181048/



git-svn-id: http://skia.googlecode.com/svn/trunk@7314 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/debugger/QT/SkDebuggerGUI.cpp b/debugger/QT/SkDebuggerGUI.cpp
index 058cb5c..812ce03 100644
--- a/debugger/QT/SkDebuggerGUI.cpp
+++ b/debugger/QT/SkDebuggerGUI.cpp
@@ -555,7 +555,9 @@
 
 void SkDebuggerGUI::saveToFile(const SkString& filename) {
     SkFILEWStream file(filename.c_str());
-    fDebugger.makePicture()->serialize(&file);
+    SkAutoTUnref<SkPicture> copy(fDebugger.copyPicture());
+
+    copy->serialize(&file);
 }
 
 void SkDebuggerGUI::loadFile(QListWidgetItem *item) {