Change undefined SkGpuRenderTarget and SkGpuTexture forward declares to GrRenderTarget and GrTextur…

src/effects/SkDisplacementMapEffect.cpp

Index: src/effects/SkDisplacementMapEffect.cpp
diff --git a/src/effects/SkDisplacementMapEffect.cpp b/src/effects/SkDisplacementMapEffect.cpp
index f81f32fb9652e4a68438cc2d66ce52a6bf63a1dc..7c99c023f8adb4cd58ed5e9869c0a2691d5b8dad 100644
--- a/src/effects/SkDisplacementMapEffect.cpp
+++ b/src/effects/SkDisplacementMapEffect.cpp
@@ -280,12 +280,12 @@ bool SkDisplacementMapEffect::filterImageGPU(Proxy* proxy, const SkBitmap& src,
     if (!SkImageFilterUtils::GetInputResultGPU(getColorInput(), proxy, src, &colorBM)) {
         return false;
     }
-    GrTexture* color = (GrTexture*) colorBM.getTexture();
+    GrTexture* color = colorBM.getTexture();
     SkBitmap displacementBM;
     if (!SkImageFilterUtils::GetInputResultGPU(getDisplacementInput(), proxy, src, &displacementBM)) {
         return false;
     }
-    GrTexture* displacement = (GrTexture*) displacementBM.getTexture();
+    GrTexture* displacement = displacementBM.getTexture();
     GrContext* context = color->getContext();
 
     GrTextureDesc desc;