Use SkPicture::ExtractBitmap callback in pdf too.

tests/PDFPrimitivesTest.cpp

Index: tests/PDFPrimitivesTest.cpp
diff --git a/tests/PDFPrimitivesTest.cpp b/tests/PDFPrimitivesTest.cpp
index b4ba0526a1f1d42daa3187cb984a1e56beebe1d4..0d623a13bb6b0a01e8ef1a3412e1dcc1822b87a5 100644
--- a/tests/PDFPrimitivesTest.cpp
+++ b/tests/PDFPrimitivesTest.cpp
@@ -39,9 +39,11 @@ private:
     SkTDArray<SkPDFObject*> fResources;
 };
 
-static bool encode_to_dct_stream(SkWStream* stream, const SkBitmap& bitmap, const SkIRect& rect) {
-    stream->writeText("DCT compessed stream.");
-    return true;
+#define DUMMY_TEXT "DCT compessed stream."
+
+static SkData* encode_to_dct_data(size_t* pixelRefOffset, const SkBitmap& bitmap) {
+    *pixelRefOffset = 0;
+    return SkData::NewWithProc(DUMMY_TEXT, sizeof(DUMMY_TEXT) - 1, NULL, NULL);
 }
 
 static bool stream_equals(const SkDynamicMemoryWStream& stream, size_t offset,
@@ -253,7 +255,7 @@ static void TestImage(skiatest::Reporter* reporter, const SkBitmap& bitmap,
     SkAutoTUnref<SkPDFDevice> dev(new SkPDFDevice(pageSize, pageSize, SkMatrix::I()));
 
     if (useDCTEncoder) {
-        dev->setDCTEncoder(encode_to_dct_stream);
+        dev->setDCTEncoder(encode_to_dct_data);
     }
 
     SkCanvas c(dev);