Eliminate SkFILE: it always is the same as FILE.

Review URL: https://codereview.chromium.org/1467533003
diff --git a/tests/DataRefTest.cpp b/tests/DataRefTest.cpp
index 177c9d3..0c7d5f4 100644
--- a/tests/DataRefTest.cpp
+++ b/tests/DataRefTest.cpp
@@ -191,7 +191,7 @@
         writer.write(s, 26);
     }
 
-    SkFILE* file = sk_fopen(path.c_str(), kRead_SkFILE_Flag);
+    FILE* file = sk_fopen(path.c_str(), kRead_SkFILE_Flag);
     SkAutoTUnref<SkData> r1(SkData::NewFromFILE(file));
     REPORTER_ASSERT(reporter, r1.get() != nullptr);
     REPORTER_ASSERT(reporter, r1->size() == 26);