Replace use of GC::alpha() in SVGImage::draw() with GC::getNormalizedAlpha()

Source/core/svg/graphics/SVGImage.cpp

Index: Source/core/svg/graphics/SVGImage.cpp
diff --git a/Source/core/svg/graphics/SVGImage.cpp b/Source/core/svg/graphics/SVGImage.cpp
index 2514abf62f7ab967d0b4986bee537b4941902271..0ecab5358c51c97dea5c3bfec64b959f6703eb2a 100644
--- a/Source/core/svg/graphics/SVGImage.cpp
+++ b/Source/core/svg/graphics/SVGImage.cpp
@@ -247,9 +247,10 @@ void SVGImage::draw(GraphicsContext* context, const FloatRect& dstRect, const Fl
     context->clip(enclosingIntRect(dstRect));
 
     bool compositingRequiresTransparencyLayer = compositeOp != CompositeSourceOver || blendMode != blink::WebBlendModeNormal;
-    bool requiresTransparencyLayer = compositingRequiresTransparencyLayer || context->alpha() < 1;
+    float opacity = context->getNormalizedAlpha() / 255.f;

[f(malita), 2014/02/27 13:23:37]

nit: just "255" (per coding style).

[fs, 2014/02/27 14:31:56]

Dropped the '.' (or this will be too binary.)

+    bool requiresTransparencyLayer = compositingRequiresTransparencyLayer || opacity < 1;
     if (requiresTransparencyLayer) {
-        context->beginTransparencyLayer(context->alpha());
+        context->beginTransparencyLayer(opacity);
         if (compositingRequiresTransparencyLayer)
             context->setCompositeOperation(CompositeSourceOver, blink::WebBlendModeNormal);
     }