Start to propagate constness of GrPipelineBuilder up the stack

src/gpu/GrTest.cpp

Index: src/gpu/GrTest.cpp
diff --git a/src/gpu/GrTest.cpp b/src/gpu/GrTest.cpp
index 5a3c014413a1ac0ac4ae67af39806e123d1001de..b070d8412a2cdfb5302d8628b5e941ee3d44baea 100644
--- a/src/gpu/GrTest.cpp
+++ b/src/gpu/GrTest.cpp
@@ -166,7 +166,7 @@ public:
                      const SkIRect& srcRect,
                      const SkIPoint& dstPoint) override { return false; };
 
-    bool initCopySurfaceDstDesc(const GrSurface* src, GrSurfaceDesc* desc) override {
+    bool initCopySurfaceDstDesc(const GrSurface* src, GrSurfaceDesc* desc) const override {
         return false;
     }