Create new target to hold gpu test code, enable direct testing of GrEffects in GM.

gm/bleed.cpp

Index: gm/bleed.cpp
diff --git a/gm/bleed.cpp b/gm/bleed.cpp
index fad5c0f18a73f80ee66d099a7bca71964be372da..83b914681f4f593a6b2133a93f7098c14ee0f559 100644
--- a/gm/bleed.cpp
+++ b/gm/bleed.cpp
@@ -14,10 +14,6 @@
 namespace skiagm {
 extern GrContext* GetGr();
 };
-
-void GrContext::setMaxTextureSizeOverride(int maxTextureSizeOverride) {
-    fMaxTextureSizeOverride = maxTextureSizeOverride;
-}
 #endif
 
 // Create a black&white checked texture with a 1-pixel red ring