iOS: cd into Documents folder at startup

CQ_INCLUDE_TRYBOTS=skia.primary:Test-iOS-Clang-iPadMini4-GPU-GX6450-arm-Release

Change-Id: I7beadad742bc9444491c7a315a827297a636d70d
Reviewed-on: https://skia-review.googlesource.com/8049
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index c2afca6..4e1da2b 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -23,6 +23,7 @@
 #include "SKPAnimationBench.h"
 #include "SKPBench.h"
 #include "Stats.h"
+#include "ios_utils.h"
 
 #include "SkAndroidCodec.h"
 #include "SkAutoMalloc.h"
@@ -1096,6 +1097,9 @@
 
 int nanobench_main();
 int nanobench_main() {
+#if defined(SK_BUILD_FOR_IOS)
+    cd_Documents();
+#endif
     SetupCrashHandler();
     SkAutoGraphics ag;
     SkTaskGroup::Enabler enabled(FLAGS_threads);