Add path utils, plus a test for it.

gm/image.cpp

Index: gm/image.cpp
diff --git a/gm/image.cpp b/gm/image.cpp
index 8578e510bad28478a911ef2606d04d96037df010..5dea17f2c618392574a51661fa89eb0c356e9f5e 100644
--- a/gm/image.cpp
+++ b/gm/image.cpp
@@ -8,8 +8,9 @@
 #include "gm.h"
 #include "SkSurface.h"
 #include "SkCanvas.h"
-#include "SkStream.h"
 #include "SkData.h"
+#include "SkOSPathUtils.h"
+#include "SkStream.h"
 
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
@@ -30,8 +31,8 @@ static SkData* fileToData(const char path[]) {
     return SkData::NewFromMalloc(mem, size);
 }
 
-static void drawJpeg(SkCanvas* canvas, const SkISize& size) {
-    SkAutoDataUnref data(fileToData("/Users/mike/Downloads/skia.google.jpeg"));

[epoger, 2013/05/22 17:33:58]

What the .. ???  Why wasn't this causing failures before?  Is it not exercised
anywhere?

[scroggo, 2013/05/23 15:29:33]

It fails silently - NewEncodedData will return a NULL image if data is empty.
The baseline for this test was never created on Mike's machine, so the expected
image doesn't have this picture.

+static void drawJpeg(SkString filename, SkCanvas* canvas, const SkISize& size) {
+    SkAutoDataUnref data(fileToData(filename.c_str()));
     SkImage* image = SkImage::NewEncodedData(data);
     if (image) {
         SkAutoCanvasRestore acr(canvas, true);
@@ -123,7 +124,9 @@ protected:
     }
 
     virtual void onDraw(SkCanvas* canvas) {
-        drawJpeg(canvas, this->getISize());
+        SkString filename = SkPathJoin(INHERITED::gResourcePath.c_str(),
+                                       "CMYK.jpg");
+        drawJpeg(filename, canvas, this->getISize());
 
         canvas->scale(2, 2);