Change undefined SkGpuRenderTarget and SkGpuTexture forward declares to GrRenderTarget and GrTexture.

R=robertphillips@google.com, reed@google.com

Author: bsalomon@google.com

Review URL: https://chromiumcodereview.appspot.com/17269003

git-svn-id: http://skia.googlecode.com/svn/trunk@9775 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkDisplacementMapEffect.cpp b/src/effects/SkDisplacementMapEffect.cpp
index f81f32f..7c99c02 100644
--- a/src/effects/SkDisplacementMapEffect.cpp
+++ b/src/effects/SkDisplacementMapEffect.cpp
@@ -280,12 +280,12 @@
     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;