test (and fix) clip_restriction in canvas

BUG=skia:

Change-Id: I86d25d0fd82be35d01471fba59f77b360be5373c
Reviewed-on: https://skia-review.googlesource.com/9995
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Derek Sollenberger <djsollen@google.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/include/core/SkStream.h b/include/core/SkStream.h
index 0a53d47cf2..e10aece360 100644
--- a/include/core/SkStream.h
+++ b/include/core/SkStream.h
@@ -232,6 +232,18 @@ public:
     static int SizeOfPackedUInt(size_t value);
 };
 
+class SK_API SkNullWStream : public SkWStream {
+public:
+    SkNullWStream() : fBytesWritten(0) {}
+
+    bool write(const void*, size_t n) override { fBytesWritten += n; return true; }
+    void flush() override {}
+    size_t bytesWritten() const override { return fBytesWritten; }
+
+private:
+    size_t fBytesWritten;
+};
+
 ////////////////////////////////////////////////////////////////////////////////////////
 
 #include <stdio.h>