remove SkMemoryWStream -- unused externally

BUG=skia:

Change-Id: Idbc9af4e703238871f56f623cd616fb7a5e686d3
Reviewed-on: https://skia-review.googlesource.com/6727
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/tests/PathOpsOpRectThreadedTest.cpp b/tests/PathOpsOpRectThreadedTest.cpp
index 5761572..e904a8d 100644
--- a/tests/PathOpsOpRectThreadedTest.cpp
+++ b/tests/PathOpsOpRectThreadedTest.cpp
@@ -64,7 +64,7 @@
                 pathStr.appendf("    testPathOp(reporter, path, pathB, %s, filename);\n",
                         SkPathOpsDebug::OpStr((SkPathOp) op));
                 pathStr.appendf("}\n\n");
-                outputProgress(state.fPathStr, pathStr.c_str(), (SkPathOp) op);
+                state.outputProgress(pathStr.c_str(), (SkPathOp) op);
             }
             if (!testPathOp(state.fReporter, pathA, pathB, (SkPathOp) op, "rects")) {
                 if (state.fReporter->verbose()) {