Add file access modes to sk_exists.

src/ports/SkOSFile_stdio.cpp

Index: src/ports/SkOSFile_stdio.cpp
diff --git a/src/ports/SkOSFile_stdio.cpp b/src/ports/SkOSFile_stdio.cpp
index ad26c807c79e45a6b5e30b367e7eb4c6b62d551e..2fd89c5fe0ae831958a32bf4f3438c62be484065 100644
--- a/src/ports/SkOSFile_stdio.cpp
+++ b/src/ports/SkOSFile_stdio.cpp
@@ -123,11 +123,18 @@ void sk_fclose(SkFILE* f) {
     ::fclose((FILE*)f);
 }
 
-bool sk_exists(const char *path) {
+bool sk_exists(const char *path, SkFILE_Flags flags) {
+    int mode = 0;

[mtklein, 2014/07/10 21:03:30]

  // F_OK
?

[bungeman-skia, 2014/07/10 21:50:07]

Done.

+    if (flags & kRead_SkFILE_Flag) {
+        mode |= 4; //R_OK
+    }
+    if (flags & kWrite_SkFILE_Flag) {
+        mode |= 2; //W_OK
+    }
 #ifdef _WIN32
-    return (0 == _access(path, 0));
+    return (0 == _access(path, mode));
 #else
-    return (0 == access(path, 0));
+    return (0 == access(path, mode));
 #endif
 }