Fix MultiPictureDraw issues with GpuImageDecodeController

cc/test/skia_common.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/test/skia_common.h"
 
 #include <stddef.h>
 
 #include "cc/playback/display_item_list.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkImageGenerator.h"
+#include "third_party/skia/include/core/SkPixmap.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/skia_util.h"
 
 namespace cc {
 
 namespace {
 
 class TestImageGenerator : public SkImageGenerator {
  public:
   explicit TestImageGenerator(const SkImageInfo& info)
-      : SkImageGenerator(info) {}
+      : SkImageGenerator(info),
+        image_backing_memory_(info.getSafeSize(info.minRowBytes()), 0),
+        image_pixmap_(info, image_backing_memory_.data(), info.minRowBytes()) {}
+
+ protected:
+  bool onGetPixels(const SkImageInfo& info,
+                   void* pixels,
+                   size_t rowBytes,
+                   SkPMColor ctable[],
+                   int* ctableCount) override {
+    return image_pixmap_.readPixels(info, pixels, rowBytes, 0, 0);
+  }
+
+ private:
+  std::vector<uint8_t> image_backing_memory_;
+  SkPixmap image_pixmap_;
 };
 
 }  // anonymous namespace
 
 void DrawDisplayList(unsigned char* buffer,
                      const gfx::Rect& layer_rect,
                      scoped_refptr<const DisplayItemList> list) {
   SkImageInfo info =
       SkImageInfo::MakeN32Premul(layer_rect.width(), layer_rect.height());
   SkBitmap bitmap;
@@ skipping 17 matching lines @@
 
   return !memcmp(pixels_a.get(), pixels_b.get(), pixel_size);
 }
 
 sk_sp<SkImage> CreateDiscardableImage(const gfx::Size& size) {
   return SkImage::MakeFromGenerator(new TestImageGenerator(
       SkImageInfo::MakeN32Premul(size.width(), size.height())));
 }
 
 }  // namespace cc