Move code to dump GrSurface as a png to helper files

src/ports/SkImagesSupport_default.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkImagesSupport.h"
+
+#if SK_SUPPORT_GPU && defined(SK_DEVELOPER)
+#include "GrSurface.h"
+#include "SkBitmap.h"
+#include "SkImageEncoder.h"
+#include <stdio.h>
+#endif
+
+// This file should be compiled to images library when images library is part of the Skia library.
+
+#if SK_SUPPORT_GPU && defined(SK_DEVELOPER)
+bool SkSaveGrSurfacePixelsAsPNG(GrSurface* surface, const char* filename) {
+    SkBitmap bm;
+    if (!bm.tryAllocPixels(SkImageInfo::MakeN32Premul(surface->width(), surface->height()))) {
+        return false;
+    }
+
+    bool result = surface->readPixels(0, 0, surface->width(), surface->height(), kSkia8888_GrPixelConfig,
+                                   bm.getPixels());
+    if (!result) {
+        SkDebugf("------ failed to read pixels for %s\n", filename);
+        return false;
+    }
+
+    // remove any previous version of surface file
+    remove(filename);
+
+    if (!SkImageEncoder::EncodeFile(filename, bm, SkImageEncoder::kPNG_Type, 100)) {
+        SkDebugf("------ failed to encode %s\n", filename);
+        remove(filename);   // remove any partial file
+        return false;
+    }
+
+    return true;
+}
+#endif