Implement image-rendering:pixelated for accelerated 2D canvases.

Source/platform/graphics/Canvas2DLayerBridge.cpp

Index: Source/platform/graphics/Canvas2DLayerBridge.cpp
diff --git a/Source/platform/graphics/Canvas2DLayerBridge.cpp b/Source/platform/graphics/Canvas2DLayerBridge.cpp
index bc23de81f21ec395ebd8295764b3516e413bbbe1..a676dc4dff550b65ea70215fce5fde5a8407089d 100644
--- a/Source/platform/graphics/Canvas2DLayerBridge.cpp
+++ b/Source/platform/graphics/Canvas2DLayerBridge.cpp
@@ -86,6 +86,7 @@ Canvas2DLayerBridge::Canvas2DLayerBridge(PassOwnPtr<WebGraphicsContext3DProvider
     , m_framesSinceMailboxRelease(0)
     , m_destructionInProgress(false)
     , m_rateLimitingEnabled(false)
+    , m_filterLevel(SkPaint::kLow_FilterLevel)
     , m_isHidden(false)
     , m_next(0)
     , m_prev(0)
@@ -102,6 +103,7 @@ Canvas2DLayerBridge::Canvas2DLayerBridge(PassOwnPtr<WebGraphicsContext3DProvider
     m_layer->setBlendBackgroundColor(opacityMode != Opaque);
     GraphicsLayer::registerContentsLayer(m_layer->layer());
     m_layer->setRateLimitContext(m_rateLimitingEnabled);
+    m_layer->setFilterLevel(m_filterLevel);
     m_canvas->setNotificationClient(this);
 #ifndef NDEBUG
     canvas2DLayerBridgeInstanceCounter.increment();
@@ -150,6 +152,15 @@ void Canvas2DLayerBridge::beginDestruction()
     ASSERT(!m_bytesAllocated);
 }
 
+void Canvas2DLayerBridge::setFilterLevel(SkPaint::FilterLevel filterLevel)
+{
+    ASSERT(!m_destructionInProgress);
+    if (m_filterLevel != filterLevel) {
+        m_filterLevel = filterLevel;
+        m_layer->setFilterLevel(m_filterLevel);
+    }
+}
+
 void Canvas2DLayerBridge::setIsHidden(bool hidden)
 {
     ASSERT(!m_destructionInProgress);