Fix 2D canvas state persistency after OffscreenCanvas.transferToImageBitmap

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2D.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2007 Alp Toker <alp@atoker.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
@@ skipping 271 matching lines @@
     SkCanvas* c = canvas()->existingDrawingCanvas();
     if (c) {
         c->resetMatrix();
         c->clipRect(SkRect::MakeWH(canvas()->width(), canvas()->height()), SkRegion::kReplace_Op);
     }
     validateStateStack();
 }
 
 void CanvasRenderingContext2D::restoreCanvasMatrixClipStack(SkCanvas* c) const
 {
-    if (!c)
-        return;
-    HeapVector<Member<CanvasRenderingContext2DState>>::const_iterator currState;
-    ASSERT(m_stateStack.begin() < m_stateStack.end());
-    for (currState = m_stateStack.begin(); currState < m_stateStack.end(); currState++) {
-        c->setMatrix(SkMatrix::I());
-        currState->get()->playbackClips(c);
-        c->setMatrix(affineTransformToSkMatrix(currState->get()->transform()));
-        c->save();
-    }
-    c->restore();
+    restoreMatrixClipStack(c);
 }
 
 bool CanvasRenderingContext2D::shouldAntialias() const
 {
     return state().shouldAntialias();
 }
 
 void CanvasRenderingContext2D::setShouldAntialias(bool doAA)
 {
     modifiableState().setShouldAntialias(doAA);
@@ skipping 747 matching lines @@
 
 unsigned CanvasRenderingContext2D::hitRegionsCount() const
 {
     if (m_hitRegionManager)
         return m_hitRegionManager->getHitRegionsCount();
 
     return 0;
 }
 
 } // namespace blink