Make OffscreenCanvasRenderingContext2D renderable on a worker

third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DState.cpp

Index: third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DState.cpp
diff --git a/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DState.cpp b/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DState.cpp
index 438a159f3daabc6c64b661a26776ce4eb54e773d..a381eb5918afad26f9b7b43925ea060fd0b65a44 100644
--- a/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DState.cpp
+++ b/third_party/WebKit/Source/modules/canvas2d/CanvasRenderingContext2DState.cpp
@@ -12,12 +12,11 @@
 #include "core/paint/FilterEffectBuilder.h"
 #include "core/style/ComputedStyle.h"
 #include "core/svg/SVGFilterElement.h"
+#include "modules/canvas2d/BaseRenderingContext2D.h"
 #include "modules/canvas2d/CanvasGradient.h"
 #include "modules/canvas2d/CanvasPattern.h"
-#include "modules/canvas2d/CanvasRenderingContext2D.h"
 #include "modules/canvas2d/CanvasStyle.h"
 #include "platform/graphics/DrawLooperBuilder.h"
-#include "platform/graphics/filters/FilterOperation.h"
 #include "platform/graphics/filters/SkiaImageFilterBuilder.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "third_party/skia/include/effects/SkDashPathEffect.h"
@@ -293,13 +292,7 @@ void CanvasRenderingContext2DState::resetTransform()
     m_isTransformInvertible = true;
 }
 
-static void updateFilterReferences(HTMLCanvasElement* canvasElement, CanvasRenderingContext2D* context, const FilterOperations& filters)
-{
-    context->clearFilterReferences();
-    context->addFilterReferences(filters, canvasElement->document());
-}
-
-SkImageFilter* CanvasRenderingContext2DState::getFilter(Element* styleResolutionHost, const Font& font, IntSize canvasSize, CanvasRenderingContext2D* context) const
+SkImageFilter* CanvasRenderingContext2DState::getFilter(Element* styleResolutionHost, const Font* font, IntSize canvasSize, BaseRenderingContext2D* context) const
 {
     if (!m_filterValue)
         return nullptr;
@@ -307,13 +300,16 @@ SkImageFilter* CanvasRenderingContext2DState::getFilter(Element* styleResolution
     if (!m_resolvedFilter) {
         RefPtr<ComputedStyle> filterStyle = ComputedStyle::create();
         // Must set font in case the filter uses any font-relative units (em, ex)
-        filterStyle->setFont(font);
-
-        StyleResolverState resolverState(styleResolutionHost->document(), styleResolutionHost, filterStyle.get());
-        resolverState.setStyle(filterStyle);
+        if (font)
+            filterStyle->setFont(*font);
+
+        if (styleResolutionHost) {
+            StyleResolverState resolverState(styleResolutionHost->document(), styleResolutionHost, filterStyle.get());
+            resolverState.setStyle(filterStyle);
+            StyleBuilder::applyProperty(CSSPropertyWebkitFilter, resolverState, m_filterValue.get());
+            resolverState.loadPendingResources();
+        }
 
-        StyleBuilder::applyProperty(CSSPropertyWebkitFilter, resolverState, m_filterValue.get());
-        resolverState.loadPendingResources();
         RefPtrWillBeRawPtr<FilterEffectBuilder> filterEffectBuilder = FilterEffectBuilder::create();
 
         // We can't reuse m_fillPaint and m_strokePaint for the filter, since these incorporate
@@ -332,13 +328,13 @@ SkImageFilter* CanvasRenderingContext2DState::getFilter(Element* styleResolution
         RefPtrWillBeRawPtr<FilterEffect> lastEffect = filterEffectBuilder->lastEffect();
         m_resolvedFilter = imageFilterBuilder.build(lastEffect.get(), ColorSpaceDeviceRGB);
         if (m_resolvedFilter)
-            updateFilterReferences(toHTMLCanvasElement(styleResolutionHost), context, filterStyle->filter());
+            context->updateFilterReferences(filterStyle->filter());
     }
 
     return m_resolvedFilter.get();
 }
 
-bool CanvasRenderingContext2DState::hasFilter(Element* styleResolutionHost, const Font& font, IntSize canvasSize, CanvasRenderingContext2D* context) const
+bool CanvasRenderingContext2DState::hasFilter(Element* styleResolutionHost, const Font* font, IntSize canvasSize, BaseRenderingContext2D* context) const
 {
     // Checking for a non-null m_filterValue isn't sufficient, since this value
     // might refer to a non-existent filter.