SkPDF: Deal with missing ColorTable (don't assert)

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"
 #include "SkImage_Base.h"
 #include "SkJpegInfo.h"
 #include "SkPDFBitmap.h"
 #include "SkPDFCanon.h"
 #include "SkStream.h"
 #include "SkUnPreMultiply.h"
 
 void image_get_ro_pixels(const SkImage* image, SkBitmap* dst) {
     if(as_IB(image)->getROPixels(dst)
        && dst->dimensions() == image->dimensions()) {
-        return;
+        if (dst->colorType() != kIndex_8_SkColorType) {
+            return;
+        }
+        // We must check to see if the bitmap has a color table.
+        SkAutoLockPixels autoLockPixels(*dst);
+        if (!dst->getColorTable()) {
+            // We can't use an indexed bitmap with no colortable.
+            dst->reset();
+        } else {
+            return;
+        }
     }
     // no pixels or wrong size: fill with zeros.
     SkAlphaType at = image->isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
     dst->setInfo(SkImageInfo::MakeN32(image->width(), image->height(), at));
 }
 
 bool image_compute_is_opaque(const SkImage* image) {
     if (image->isOpaque()) {
         return true;
     }
@@ skipping 287 matching lines @@
 
 static void emit_image_xobject(SkWStream* stream,
                                const SkImage* image,
                                bool alpha,
                                SkPDFObject* smask,
                                const SkPDFObjNumMap& objNumMap,
                                const SkPDFSubstituteMap& substitutes) {
     SkBitmap bitmap;
     image_get_ro_pixels(image, &bitmap);      // TODO(halcanary): test
     SkAutoLockPixels autoLockPixels(bitmap);  // with malformed images.
-    SkASSERT(bitmap.colorType() != kIndex_8_SkColorType ||
-             bitmap.getColorTable());
 
     // Write to a temporary buffer to get the compressed length.
     SkDynamicMemoryWStream buffer;
     SkDeflateWStream deflateWStream(&buffer);
     if (alpha) {
         bitmap_alpha_to_a8(bitmap, &deflateWStream);
     } else {
         bitmap_to_pdf_pixels(bitmap, &deflateWStream);
     }
     deflateWStream.finalize();  // call before detachAsStream().
@@ skipping 132 matching lines @@
             return new PDFJpegBitmap(info.fSize, data, yuv);
         }
     }
     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);
 }