Add raw pixel serialization fallback for SkImages that cannot be encoded.

src/core/SkReadBuffer.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkErrorInternals.h"
 #include "SkImage.h"
@@ skipping 258 matching lines @@
 } // anonymous namespace
 
 SkImage* SkReadBuffer::readImage() {
     int width = this->read32();
     int height = this->read32();
     if (width <= 0 || height <= 0) {    // SkImage never has a zero dimension
         this->validate(false);
         return nullptr;
     }
 
-    sk_sp<SkData> encoded(this->readByteArrayAsData());
-    if (encoded->size() == 0) {
-        // The image could not be encoded at serialization time - return an empty placeholder.
+    auto placeholder = [=] {
         return SkImage::MakeFromGenerator(
             new EmptyImageGenerator(SkImageInfo::MakeN32Premul(width, height))).release();
+    };
+
+    uint32_t encoded_size = this->getArrayCount();
+    if (encoded_size == 0) {
+        // The image could not be encoded at serialization time - return an empty placeholder.
+        (void)this->readUInt();  // Swallow that encoded_size == 0 sentinel.
+        return placeholder();
     }
+    if (encoded_size == 1) {
+        // We had to encode the image as raw pixels via SkBitmap.
+        (void)this->readUInt();  // Swallow that encoded_size == 1 sentinel.
+        SkBitmap bm;
+        if (SkBitmap::ReadRawPixels(this, &bm)) {
+            return SkImage::MakeFromBitmap(bm).release();
+        }
+        return placeholder();
+    }
+
+    // The SkImage encoded itself.
+    sk_sp<SkData> encoded(this->readByteArrayAsData());
 
     int originX = this->read32();
     int originY = this->read32();
     if (originX < 0 || originY < 0) {
         this->validate(false);
         return nullptr;
     }
 
     const SkIRect subset = SkIRect::MakeXYWH(originX, originY, width, height);
     SkImage* image = SkImage::MakeFromEncoded(std::move(encoded), &subset).release();
@@ skipping 76 matching lines @@
         if (sizeRecorded != sizeRead) {
             this->validate(false);
             return nullptr;
         }
     } else {
         // we must skip the remaining data
         fReader.skip(sizeRecorded);
     }
     return obj.release();
 }