Revert of Discard atlas after every MultiPictureDraw::draw

src/gpu/GrLayerHoister.cpp

Index: src/gpu/GrLayerHoister.cpp
diff --git a/src/gpu/GrLayerHoister.cpp b/src/gpu/GrLayerHoister.cpp
index 1ba0d8e5454e4763a71da98a11ccd19e0d5d7547..272f0446b8c65dbe7145e8ff2f1185db7949e474 100644
--- a/src/gpu/GrLayerHoister.cpp
+++ b/src/gpu/GrLayerHoister.cpp
@@ -314,16 +314,13 @@
         layerCache->removeUse(layers[i].fLayer);
     }
 
-    SkDEBUGCODE(layerCache->validate();)
-}
-
-void GrLayerHoister::PurgeCache(GrContext* context) {
-#if !GR_CACHE_HOISTED_LAYERS
-    GrLayerCache* layerCache = context->getLayerCache();
-
+#if DISABLE_CACHING
     // This code completely clears out the atlas. It is required when
     // caching is disabled so the atlas doesn't fill up and force more
     // free floating layers
     layerCache->purgeAll();
 #endif
-}
+
+    SkDEBUGCODE(layerCache->validate();)
+}
+