Web setting for canvas2d msaa

Source/core/html/HTMLCanvasElement.cpp

Index: Source/core/html/HTMLCanvasElement.cpp
diff --git a/Source/core/html/HTMLCanvasElement.cpp b/Source/core/html/HTMLCanvasElement.cpp
index 94f0dc4c53dd9baa8570ad755f88eff35ea97a7c..6857332252c8661930986942682514cd7c86bcf7 100644
--- a/Source/core/html/HTMLCanvasElement.cpp
+++ b/Source/core/html/HTMLCanvasElement.cpp
@@ -497,8 +497,11 @@ void HTMLCanvasElement::createImageBuffer()
         return;
 
     RenderingMode renderingMode = shouldAccelerate(bufferSize) ? Accelerated : UnacceleratedNonPlatformBuffer;
+    int msaaSampleCount = 0;
+    if (Accelerated == renderingMode && document().settings()->antialiased2dCanvasEnabled())

[Stephen White, 2013/10/18 20:13:12]

Nit: blink style doesn't reverse the == operands (although it doesn't disallow
it either).

[bsalomon, 2013/10/21 13:48:47]

Done, to be more consistent other blink code.

+        msaaSampleCount = document().settings()->accelerated2dCanvasMSAASampleCount();
     OpacityMode opacityMode = !m_context || m_context->hasAlpha() ? NonOpaque : Opaque;
-    m_imageBuffer = ImageBuffer::create(size(), m_deviceScaleFactor, renderingMode, opacityMode);
+    m_imageBuffer = ImageBuffer::create(size(), m_deviceScaleFactor, renderingMode, opacityMode, msaaSampleCount);
     if (!m_imageBuffer)
         return;
     setExternallyAllocatedMemory(4 * width() * height());