Add path utils, plus a test for it.

src/utils/SkOSFile.cpp

Index: src/utils/SkOSFile.cpp
diff --git a/src/utils/SkOSFile.cpp b/src/utils/SkOSFile.cpp
index 478a0cc44868e4376e5839a052a151729e0d7ff6..016e708ce64b2c0e7d146b7a6050ba132acb412e 100644
--- a/src/utils/SkOSFile.cpp
+++ b/src/utils/SkOSFile.cpp
@@ -226,4 +226,27 @@ bool SkOSFile::Iter::next(SkString* name, bool getDir)
     return false;
 }
 
+namespace SkOSPathUtils {

[epoger, 2013/05/24 16:42:55]

I agree that SkOSFile is declared/defined in a strange mix of locations.

Luckily, I don't think that's your problem to solve in this CL.  So I think
where you put stuff is fine.

+    SkString SkPathJoin(const char *rootPath, const char *relativePath) {
+        SkString result(rootPath);
+        if (!result.endsWith(SkPATH_SEPARATOR)) {
+            result.appendUnichar(SkPATH_SEPARATOR);
+        }
+        result.append(relativePath);
+        return result;
+    }
+
+    SkString SkBasename(const char* fullPath) {
+        if (!fullPath) {
+            return SkString();
+        }
+        const char* filename = strrchr(fullPath, SkPATH_SEPARATOR);
+        if (NULL == filename) {
+            filename = fullPath;
+        } else {
+            ++filename;
+        }
+        return SkString(filename);
+    }
+}
 #endif