SkPDF: Let client re-encode JPGs if they want to

src/pdf/SkPDFBitmap.cpp

Index: src/pdf/SkPDFBitmap.cpp
diff --git a/src/pdf/SkPDFBitmap.cpp b/src/pdf/SkPDFBitmap.cpp
index 4e49db518d802896ed069a75fe4f3f66d9bd0bb2..e067ed1c0bb776ed66fe7f0ada974e7477d0b3a5 100644
--- a/src/pdf/SkPDFBitmap.cpp
+++ b/src/pdf/SkPDFBitmap.cpp
@@ -472,7 +472,12 @@ SkPDFObject* SkPDFCreateBitmapObject(const SkImage* image,
                                      SkPixelSerializer* pixelSerializer) {
     SkAutoTUnref<SkData> data(image->refEncoded());
     SkJFIFInfo info;
-    if (data && SkIsJFIF(data, &info)) {
+    if (data && SkIsJFIF(data, &info) &&
+        (!pixelSerializer ||
+         pixelSerializer->useEncodedData(data->data(), data->size()))) {
+        // If there is a SkPixelSerializer, give it a chance to
+        // re-encode the JPEG with more compression by returning false
+        // from useEncodedData.
         bool yuv = info.fType == SkJFIFInfo::kYCbCr;
         if (info.fSize == image->dimensions()) {  // Sanity check.
             // hold on to data, not image.