Cleanup: Delete sk_tools::get_basename() in favor of SkOSPath::SkBasename().

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

Author: tfarina@chromium.org

Review URL: https://codereview.chromium.org/321693002
diff --git a/tools/bench_pictures_main.cpp b/tools/bench_pictures_main.cpp
index b79dfed..4d4116d 100644
--- a/tools/bench_pictures_main.cpp
+++ b/tools/bench_pictures_main.cpp
@@ -191,8 +191,7 @@
         return false;
     }
 
-    SkString filename;
-    sk_tools::get_basename(&filename, inputPath);
+    SkString filename = SkOSPath::SkBasename(inputPath.c_str());
 
     gWriter.bench(filename.c_str(), picture->width(), picture->height());