Make GrPipeline hold a GrRenderTargetProxy (instead of a GrRenderTarget)

In a future world where GrSurface no longer has an origin it will be
useful for the GrPipeline to be holding the GrRenderTargetProxy (which will
still have an origin).

Change-Id: I743a8cc07b6b92f8116227fb77b7c37da43cde8a
Reviewed-on: https://skia-review.googlesource.com/26804
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/ccpr/GrCCPRCoverageProcessor.h b/src/gpu/ccpr/GrCCPRCoverageProcessor.h
index 86f7d46..574cf4a 100644
--- a/src/gpu/ccpr/GrCCPRCoverageProcessor.h
+++ b/src/gpu/ccpr/GrCCPRCoverageProcessor.h
@@ -104,7 +104,7 @@
     void enableDebugVisualizations() { fDebugVisualizations = true; }
     bool debugVisualizations() const { return fDebugVisualizations; }
 
-    static void Validate(GrRenderTarget* atlasTexture);
+    static void Validate(GrRenderTargetProxy* atlasProxy);
 #endif
 
     class PrimitiveProcessor;