Reland 'Add path utils, plus a test for it.'

gm/factory.cpp

 /*

[epoger, 2013/05/28 17:48:11]

Would using the Commit Queue (or its trybots [1]) have prevented
https://code.google.com/p/skia/source/detail?r=9277 from landing in such a way
that it broke the Windows build?

If not, please file a bug.

[1] - by "or its trybots", I mean running "tools/submit_try $CHANGENAME --bot
cq", which runs tryjobs on the same set of trybots that the commit queue would
use

[scroggo, 2013/05/28 17:56:36]

I suspect that it would have, although I did not suspect there was an issue of
this not building on other platforms.

  * Copyright 2012 Google Inc.
  *

[epoger, 2013/05/28 17:48:11]

IMHO, when relanding patches I think it's preferable to upload it as two
patchsets: patchset 1 which just reapplies the previous patch, and patchset 2
which fixes the bug.  That way it's easy to see what changed from the previous
attempt.

For example: https://codereview.appspot.com/7132060 ('re-land r7258 with fixes
and tests')

[scroggo, 2013/05/28 17:56:36]

I'll make a mental note to do that next time. That would have been much more
helpful, but I didn't think about it :(

  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkBitmapFactory.h"
 #include "SkCanvas.h"
 #include "SkData.h"
 #include "SkImageDecoder.h"
 #include "SkLruImageCache.h"
+#include "SkOSFile.h"
 #include "SkStream.h"
 
 namespace skiagm {
 
 /**
  *  Draw a PNG created by SkBitmapFactory.
  */
 class FactoryGM : public GM {
 public:
     FactoryGM() {}
 
 protected:
     virtual void onOnceBeforeDraw() SK_OVERRIDE {
-        SkString filename(INHERITED::gResourcePath);
-        if (!filename.endsWith("/") && !filename.endsWith("\\")) {
-            filename.append("/");
-        }
-
         // Copyright-free file from http://openclipart.org/detail/29213/paper-plane-by-ddoo
-        filename.append("plane.png");
+        SkString filename = SkOSPath::SkPathJoin(INHERITED::gResourcePath.c_str(),
+                                                 "plane.png");
 
         SkAutoTUnref<SkStream> stream(SkStream::NewFromFile(filename.c_str()));
         if (NULL != stream.get()) {
             stream->rewind();
             size_t length = stream->getLength();
             void* buffer = sk_malloc_throw(length);
             stream->read(buffer, length);
             SkAutoDataUnref data(SkData::NewFromMalloc(buffer, length));
             SkBitmapFactory factory(&SkImageDecoder::DecodeMemoryToTarget);
             // Create a cache which will boot the pixels out anytime the
@@ skipping 21 matching lines @@
 
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new FactoryGM; }
 static GMRegistry reg(MyFactory);
 
 }