Fix 2D canvas state persistency after OffscreenCanvas.transferToImageBitmap

third_party/WebKit/Source/modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.cpp

 // Copyright 2016 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 "modules/offscreencanvas2d/OffscreenCanvasRenderingContext2D.h"
 
 #include "bindings/modules/v8/OffscreenCanvasRenderingContext2DOrWebGLRenderingContextOrWebGL2RenderingContext.h"
 #include "core/frame/ImageBitmap.h"
 #include "platform/graphics/ImageBuffer.h"
 #include "platform/graphics/StaticBitmapImage.h"
@@ skipping 55 matching lines @@
 {
     return !!m_imageBuffer;
 }
 
 ImageBuffer* OffscreenCanvasRenderingContext2D::imageBuffer() const
 {
     if (!m_imageBuffer) {
         // TODO: crbug.com/593514 Add support for GPU rendering
         OffscreenCanvasRenderingContext2D* nonConstThis = const_cast<OffscreenCanvasRenderingContext2D*>(this);
         nonConstThis->m_imageBuffer = ImageBuffer::create(IntSize(width(), height()), m_hasAlpha ? NonOpaque : Opaque, InitializeImagePixels);
-        // TODO: crbug.com/593349 Restore matrix and clip state on the new ImageBuffer.
+
+        if (m_needsMatrixClipRestore) {
+            restoreMatrixClipStack(m_imageBuffer->canvas());
+            nonConstThis->m_needsMatrixClipRestore = false;
+        }
     }
 
     return m_imageBuffer.get();
 }
 
 ImageBitmap* OffscreenCanvasRenderingContext2D::transferToImageBitmap(ExceptionState& exceptionState)
 {
     if (!imageBuffer())
         return nullptr;
     // TODO: crbug.com/593514 Add support for GPU rendering
     RefPtr<SkImage> skImage = m_imageBuffer->newSkImageSnapshot(PreferNoAcceleration, SnapshotReasonUnknown);
     RefPtr<StaticBitmapImage> image = StaticBitmapImage::create(skImage.release());
     image->setOriginClean(this->originClean());
     m_imageBuffer.reset(); // "Transfer" means no retained buffer
+    m_needsMatrixClipRestore = true;
     return ImageBitmap::create(image.release());
 }
 
 void OffscreenCanvasRenderingContext2D::setOffscreenCanvasGetContextResult(OffscreenRenderingContext& result)
 {
     result.setOffscreenCanvasRenderingContext2D(this);
 }
 
 bool OffscreenCanvasRenderingContext2D::parseColorOrCurrentColor(Color& color, const String& colorString) const
 {
@@ skipping 51 matching lines @@
     }
 #endif
 }
 
 bool OffscreenCanvasRenderingContext2D::isContextLost() const
 {
     return false;
 }
 
 }