update devicelooper to skip internal tiles that are empty, and unittests

BUG=

Review URL: https://codereview.chromium.org/23463040

git-svn-id: http://skia.googlecode.com/svn/trunk@11331 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SamplePictFile.cpp b/samplecode/SamplePictFile.cpp
index 867118d..b8298d4 100644
--- a/samplecode/SamplePictFile.cpp
+++ b/samplecode/SamplePictFile.cpp
@@ -27,6 +27,7 @@
 #include "SkXfermode.h"
 
 #include "SkStream.h"
+#include "SkSurface.h"
 #include "SkXMLParser.h"
 
 class PictFileView : public SampleView {
@@ -53,6 +54,11 @@
                 SkDebugf("coun't load picture at \"path\"\n", path);
             }
 
+            if (false) {
+                SkSurface* surf = SkSurface::NewRasterPMColor(pic->width(), pic->height());
+                surf->getCanvas()->drawPicture(*pic);
+                surf->unref();
+            }
             if (false) { // re-record
                 SkPicture p2;
                 pic->draw(p2.beginRecording(pic->width(), pic->height()));