Fix image filters for PDF backend.

src/core/SkDeviceImageFilterProxy.h

Index: src/core/SkDeviceImageFilterProxy.h
diff --git a/src/core/SkDeviceImageFilterProxy.h b/src/core/SkDeviceImageFilterProxy.h
index 5ee563484ee34cf88869863283525b601d59b0f7..0b83b1a81eaf04e1104d8642192a6a7649d58493 100644
--- a/src/core/SkDeviceImageFilterProxy.h
+++ b/src/core/SkDeviceImageFilterProxy.h
@@ -15,7 +15,7 @@ public:
     SkDeviceImageFilterProxy(SkBaseDevice* device) : fDevice(device) {}
 
     virtual SkBaseDevice* createDevice(int w, int h) SK_OVERRIDE {
-        return fDevice->createCompatibleDevice(SkImageInfo::MakeN32Premul(w, h));
+        return fDevice->createCompatibleDeviceForImageFilter(SkImageInfo::MakeN32Premul(w, h));
     }
     virtual bool canHandleImageFilter(const SkImageFilter* filter) SK_OVERRIDE {
         return fDevice->canHandleImageFilter(filter);