Cleanup debugger's handling of bad input files

https://codereview.appspot.com/7308062/



git-svn-id: http://skia.googlecode.com/svn/trunk@7654 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/debugger/QT/SkDebuggerGUI.cpp b/debugger/QT/SkDebuggerGUI.cpp
index 890c607..a823c19 100644
--- a/debugger/QT/SkDebuggerGUI.cpp
+++ b/debugger/QT/SkDebuggerGUI.cpp
@@ -1001,7 +1001,16 @@
     fFileName = fileName;
     fLoading = true;
     SkStream* stream = SkNEW_ARGS(SkFILEStream, (fileName.c_str()));
-    SkOffsetPicture* picture = SkNEW_ARGS(SkOffsetPicture, (stream, NULL, &SkImageDecoder::DecodeStream));
+
+    bool success = false;
+
+    SkOffsetPicture* picture = SkNEW_ARGS(SkOffsetPicture, (stream, &success, &SkImageDecoder::DecodeStream));
+
+    if (!success) {
+        QMessageBox::critical(this, "Error loading file", "Couldn't read file, sorry.");
+        SkSafeUnref(stream);
+        return;
+    }
 
     fCanvasWidget.resetWidgetTransform();
     fDebugger.loadPicture(picture);