Re-arrange some null pointer checks in HTMLCanvasElement.cpp

third_party/WebKit/Source/core/html/HTMLCanvasElement.cpp

 /*
  * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 93 matching lines @@
 // gpuBufferCount in ImageBuffer::updateGPUMemoryUsage() and 4 means four bytes
 // per pixel per buffer.
 const int MaxGlobalGPUMemoryUsage =
     4000000 * MaxGlobalAcceleratedImageBufferCount;
 
 // A default value of quality argument for toDataURL and toBlob
 // It is in an invalid range (outside 0.0 - 1.0) so that it will not be
 // misinterpreted as a user-input value
 const int UndefinedQualityValue = -1.0;
 
-PassRefPtr<Image> createTransparentImage(const IntSize& size) {
+sk_sp<SkImage> createTransparentSkImage(const IntSize& size) {
   DCHECK(ImageBuffer::canCreateImageBuffer(size));
   sk_sp<SkSurface> surface =
       SkSurface::MakeRasterN32Premul(size.width(), size.height());
-  return surface ? StaticBitmapImage::create(surface->makeImageSnapshot())
-                 : nullptr;
+  return surface->makeImageSnapshot();
+}
+
+PassRefPtr<Image> createTransparentImage(const IntSize& size) {
+  sk_sp<SkImage> image = createTransparentSkImage(size);
+  return image ? StaticBitmapImage::create(image) : nullptr;
 }
 
 }  // namespace
 
 inline HTMLCanvasElement::HTMLCanvasElement(Document& document)
     : HTMLElement(canvasTag, document),
       ContextLifecycleObserver(&document),
       PageVisibilityObserver(document.page()),
       m_size(DefaultWidth, DefaultHeight),
       m_context(this, nullptr),
@@ skipping 1093 matching lines @@
     *status = InvalidSourceImageStatus;
     return nullptr;
   }
 
   if (placeholderFrame()) {
     *status = NormalSourceImageStatus;
     return placeholderFrame();
   }
 
   if (!m_context) {
-    *status = NormalSourceImageStatus;
-    return createTransparentImage(size());
+    RefPtr<Image> result = createTransparentImage(size());
+    *status = result ? NormalSourceImageStatus : InvalidSourceImageStatus;
+    return result;
   }
 
   if (m_context->getContextType() == CanvasRenderingContext::ContextImageBitmap)
     return m_context->getImage(hint, reason);
 
   sk_sp<SkImage> skImage;
   // TODO(ccameron): Canvas should produce sRGB images.
   // https://crbug.com/672299
   if (m_context->is3d()) {
     // Because WebGL sources always require making a copy of the back buffer, we
     // use paintRenderingResultsToCanvas instead of getImage in order to keep a
     // cached copy of the backing in the canvas's ImageBuffer.
     renderingContext()->paintRenderingResultsToCanvas(BackBuffer);
-    skImage = hasImageBuffer()
-                  ? buffer()->newSkImageSnapshot(hint, reason)
-                  : createTransparentImage(size())->imageForCurrentFrame(
-                        ColorBehavior::transformToGlobalTarget());
+    if (hasImageBuffer()) {
+      skImage = buffer()->newSkImageSnapshot(hint, reason);
+    } else {
+      skImage = createTransparentSkImage(size());
+    }
   } else {
     if (ExpensiveCanvasHeuristicParameters::
             DisableAccelerationToAvoidReadbacks &&
         !RuntimeEnabledFeatures::canvas2dFixedRenderingModeEnabled() &&
         hint == PreferNoAcceleration && m_context->isAccelerated() &&
         hasImageBuffer())
       buffer()->disableAcceleration();
-    RefPtr<blink::Image> image = renderingContext()->getImage(hint, reason);
-    skImage = image
-                  ? image->imageForCurrentFrame(
-                        ColorBehavior::transformToGlobalTarget())
-                  : createTransparentImage(size())->imageForCurrentFrame(
-                        ColorBehavior::transformToGlobalTarget());
+    RefPtr<Image> image = renderingContext()->getImage(hint, reason);
+    if (image) {
+      skImage =
+          image->imageForCurrentFrame(ColorBehavior::transformToGlobalTarget());
+    } else {
+      skImage = createTransparentSkImage(size());
+    }
   }
 
   if (skImage) {
     *status = NormalSourceImageStatus;
     return StaticBitmapImage::create(std::move(skImage));
   }
 
   *status = InvalidSourceImageStatus;
   return nullptr;
 }
@@ skipping 131 matching lines @@
   m_surfaceLayerBridge = WTF::wrapUnique(new CanvasSurfaceLayerBridge(this));
   // Creates a placeholder layer first before Surface is created.
   m_surfaceLayerBridge->createSolidColorLayer();
 }
 
 void HTMLCanvasElement::OnWebLayerReplaced() {
   setNeedsCompositingUpdate();
 }
 
 }  // namespace blink