Cleanup: Rename SkOSPath functions.

Mostly for brevity and matches better with Python:

Python           | Old C++                 | New C++
os.path.join     | SkOSPath::SkPathJoin    | SkOSPath::Join
os.path.basename | SkOSPath::SkBasename    | SkOSPath::Basename

BUG=None
TEST=make all
R=mtklein@google.com, bsalomon@google.com

Author: tfarina@chromium.org

Review URL: https://codereview.chromium.org/428443002
diff --git a/experimental/PdfViewer/pdf_viewer_main.cpp b/experimental/PdfViewer/pdf_viewer_main.cpp
index c1b0284..fab3dc0 100644
--- a/experimental/PdfViewer/pdf_viewer_main.cpp
+++ b/experimental/PdfViewer/pdf_viewer_main.cpp
@@ -103,7 +103,7 @@
 static bool make_output_filepath(SkString* path, const SkString& dir,
                                  const SkString& name,
                                  int page) {
-    *path = SkOSPath::SkPathJoin(dir.c_str(), name.c_str());
+    *path = SkOSPath::Join(dir.c_str(), name.c_str());
     return add_page_and_replace_filename_extension(path, page,
                                                    PDF_FILE_EXTENSION,
                                                    PNG_FILE_EXTENSION);
@@ -221,7 +221,7 @@
 static bool process_pdf(const SkString& inputPath, const SkString& outputDir) {
     SkDebugf("Loading PDF:  %s\n", inputPath.c_str());
 
-    SkString inputFilename = SkOSPath::SkBasename(inputPath.c_str());
+    SkString inputFilename = SkOSPath::Basename(inputPath.c_str());
 
     SkAutoTDelete<SkPdfRenderer> renderer(SkPdfRenderer::CreateFromFile(inputPath.c_str()));
     if (NULL == renderer.get()) {
@@ -299,7 +299,7 @@
         SkOSFile::Iter iter(input, PDF_FILE_EXTENSION);
         SkString inputFilename;
         while (iter.next(&inputFilename)) {
-            SkString inputPath = SkOSPath::SkPathJoin(input, inputFilename.c_str());
+            SkString inputPath = SkOSPath::Join(input, inputFilename.c_str());
             if (!process_pdf(inputPath, outputDir)) {
                 ++failures;
             }