Recycle OffscreenBuffers

Change-Id: Ia2e219026f211a5308ecf8209c5f986bb888aadd
diff --git a/libs/hwui/renderthread/CanvasContext.cpp b/libs/hwui/renderthread/CanvasContext.cpp
index 1b89960..f094b2d 100644
--- a/libs/hwui/renderthread/CanvasContext.cpp
+++ b/libs/hwui/renderthread/CanvasContext.cpp
@@ -599,7 +599,7 @@
         // Make sure to release all the textures we were owning as there won't
         // be another draw
         caches.textureCache.resetMarkInUse(this);
-        caches.flush(Caches::FlushMode::Layers);
+        mRenderThread.renderState().flush(Caches::FlushMode::Layers);
     }
 }
 
@@ -609,10 +609,10 @@
 
     ATRACE_CALL();
     if (level >= TRIM_MEMORY_COMPLETE) {
-        Caches::getInstance().flush(Caches::FlushMode::Full);
+        thread.renderState().flush(Caches::FlushMode::Full);
         thread.eglManager().destroy();
     } else if (level >= TRIM_MEMORY_UI_HIDDEN) {
-        Caches::getInstance().flush(Caches::FlushMode::Moderate);
+        thread.renderState().flush(Caches::FlushMode::Moderate);
     }
 }