Maintain SkPaint in GraphicsContextState.

Source/core/html/canvas/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 530 matching lines @@
 {
     if (!(alpha >= 0 && alpha <= 1))
         return;
     if (state().m_globalAlpha == alpha)
         return;
     realizeSaves();
     modifiableState().m_globalAlpha = alpha;
     GraphicsContext* c = drawingContext();
     if (!c)
         return;
-    c->setAlpha(alpha);
+    c->setAlphaAsFloat(alpha);
 }
 
 String CanvasRenderingContext2D::globalCompositeOperation() const
 {
     return compositeOperatorName(state().m_globalComposite, state().m_globalBlend);
 }
 
 void CanvasRenderingContext2D::setGlobalCompositeOperation(const String& operation)
 {
     CompositeOperator op = CompositeSourceOver;
@@ skipping 531 matching lines @@
     if (shouldDrawShadows()) {
         context->save();
         saved = true;
         context->clearShadow();
     }
     if (state().m_globalAlpha != 1) {
         if (!saved) {
             context->save();
             saved = true;
         }
-        context->setAlpha(1);
+        context->setAlphaAsFloat(1);
     }
     if (state().m_globalComposite != CompositeSourceOver) {
         if (!saved) {
             context->save();
             saved = true;
         }
         context->setCompositeOperation(CompositeSourceOver);
     }
     context->clearRect(rect);
     if (saved)
@@ skipping 1352 matching lines @@
 {
     GraphicsContext* c = drawingContext();
     if (!c)
         return;
 
     FloatRect dirtyRect;
     if (!computeDirtyRect(path.boundingRect(), &dirtyRect))
         return;
 
     c->save();
-    c->setAlpha(1.0);
+    c->setAlphaAsFloat(1.0);
     c->clearShadow();
     c->setCompositeOperation(CompositeSourceOver, blink::WebBlendModeNormal);
 
     // These should match the style defined in html.css.
     Color focusRingColor = RenderTheme::theme().focusRingColor();
     const int focusRingWidth = 5;
     const int focusRingOutline = 0;
     c->drawFocusRing(path, focusRingWidth, focusRingOutline, focusRingColor);
 
     c->restore();
 
     didDraw(dirtyRect);
 }
 
 } // namespace WebCore