Rename backing texture testing routines

gm/imagefromyuvtextures.cpp

Index: gm/imagefromyuvtextures.cpp
diff --git a/gm/imagefromyuvtextures.cpp b/gm/imagefromyuvtextures.cpp
index dbed06fa21d80eee906a105fc57e5951a973caff..8dbfffd8311bea42abe5ada48598ced23299633d 100644
--- a/gm/imagefromyuvtextures.cpp
+++ b/gm/imagefromyuvtextures.cpp
@@ -102,9 +102,10 @@ protected:
 
         for (int i = 0; i < 3; ++i) {
             SkASSERT(fYUVBmps[i].width() == SkToInt(fYUVBmps[i].rowBytes()));
-            yuvIDs[i] = gpu->createBackendTexture(fYUVBmps[i].getPixels(),
-                                                  fYUVBmps[i].width(), fYUVBmps[i].height(),
-                                                  kAlpha_8_GrPixelConfig);
+            yuvIDs[i] = gpu->createTestingOnlyBackendTexture(fYUVBmps[i].getPixels(),
+                                                             fYUVBmps[i].width(), 
+                                                             fYUVBmps[i].height(),
+                                                             kAlpha_8_GrPixelConfig);
         }
         context->resetContext();
     }
@@ -117,7 +118,7 @@ protected:
         }
 
         for (int i = 0; i < 3; ++i) {
-            gpu->deleteBackendTexture(yuvIDs[i]);
+            gpu->deleteTestingOnlyBackendTexture(yuvIDs[i]);
         }
 
         context->resetContext();