Refactor how we handle resources path in Tests.

This idea emerged while doing https://codereview.chromium.org/321723002/
(commit 880914c35c8f7fc2e9c57134134c883baf66e538).

BUG=None
TEST=make tests && out/Debug/tests
R=mtklein@google.com

Author: tfarina@chromium.org

Review URL: https://codereview.chromium.org/346453002
diff --git a/samplecode/SampleSubpixelTranslate.cpp b/samplecode/SampleSubpixelTranslate.cpp
index afb31c1..41a0f15 100644
--- a/samplecode/SampleSubpixelTranslate.cpp
+++ b/samplecode/SampleSubpixelTranslate.cpp
@@ -1,4 +1,3 @@
-
 /*
  * Copyright 2014 Google Inc.
  *
@@ -7,10 +6,12 @@
  */
 
 #include "gm.h"
+
+#include "Resources.h"
 #include "SampleCode.h"
 #include "SkBlurMaskFilter.h"
-#include "SkColorPriv.h"
 #include "SkCanvas.h"
+#include "SkColorPriv.h"
 #include "SkImageDecoder.h"
 #include "SkRandom.h"
 #include "SkStream.h"
@@ -26,12 +27,12 @@
       : fFilename(imageFilename),
         fHorizontalVelocity(horizontalVelocity),
         fVerticalVelocity(verticalVelocity) {
-      SkString path(skiagm::GM::GetResourcePath());
-      path.append("/");
-      path.append(fFilename);
+      SkString resourcePath = GetResourcePath();
+      resourcePath.append("/");
+      resourcePath.append(fFilename);
 
-      SkImageDecoder *codec = NULL;
-      SkFILEStream stream(path.c_str());
+      SkImageDecoder* codec = NULL;
+      SkFILEStream stream(resourcePath.c_str());
       if (stream.isValid()) {
           codec = SkImageDecoder::Factory(&stream);
       }