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

src/pdf/SkPDFBitmap.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorPriv.h"
 #include "SkData.h"
 #include "SkDeflate.h"
@@ skipping 454 matching lines @@
     pdf_stream_end(stream);
 }
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 
 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.
             #ifdef SK_PDF_IMAGE_STATS
             gJpegImageObjects.fetch_add(1);
             #endif
             return new PDFJpegBitmap(info.fSize, data, yuv);
         }
     }
 
@@ skipping 11 matching lines @@
         }
     }
 
     SkPDFObject* smask =
             image_compute_is_opaque(image) ? nullptr : new PDFAlphaBitmap(image);
     #ifdef SK_PDF_IMAGE_STATS
     gRegularImageObjects.fetch_add(1);
     #endif
     return new PDFDefaultBitmap(image, smask);
 }