Cleanup usage of GetResourcePath() after commit bcbc1788b478b1e54079318ad073e8490aa66fae.

There was a clean up opportunity left over after
https://skia.googlesource.com/skia/+/bcbc1788b478b1e54079318ad073e8490aa66fae, that could make use of the default parameter of GetResourcePath() function to make some call sites cleaner.

We decided to make it in a separate CL to make reviewer's and author's life easier, so we could catch errors and/or mistakes easily.

BUG=None
TEST=make all && out/Debug/dm && out/Debug/SampleApp
R=mtklein@google.com

Author: tfarina@chromium.org

Review URL: https://codereview.chromium.org/351133003
diff --git a/samplecode/SamplePicture.cpp b/samplecode/SamplePicture.cpp
index ecc5941..28256e5 100644
--- a/samplecode/SamplePicture.cpp
+++ b/samplecode/SamplePicture.cpp
@@ -37,9 +37,8 @@
 
 static SkBitmap load_bitmap() {
     SkBitmap bm;
-    SkString resourcePath = GetResourcePath();
-    SkString path = SkOSPath::SkPathJoin(resourcePath.c_str(), "mandrill_512.png");
-    SkAutoDataUnref data(SkData::NewFromFileName(path.c_str()));
+    SkString pngFilename = GetResourcePath("mandrill_512.png");
+    SkAutoDataUnref data(SkData::NewFromFileName(pngFilename.c_str()));
     if (data.get() != NULL) {
         SkInstallDiscardablePixelRef(SkDecodingImageGenerator::Create(
             data, SkDecodingImageGenerator::Options()), &bm);