Simplify GrDrawBatch uploads and token uage.

src/gpu/GrDrawingManager.cpp

Index: src/gpu/GrDrawingManager.cpp
diff --git a/src/gpu/GrDrawingManager.cpp b/src/gpu/GrDrawingManager.cpp
index 6efc286e7312b340961f072922a7bfc8e116f166..976fbb62a49e0c8ec499ce7f0a66fb6afa295cca 100644
--- a/src/gpu/GrDrawingManager.cpp
+++ b/src/gpu/GrDrawingManager.cpp
@@ -84,7 +84,7 @@ void GrDrawingManager::flush() {
         fDrawTargets[i]->drawBatches(&fFlushState);
     }
 
-    SkASSERT(fFlushState.lastFlushedToken() == fFlushState.currentToken());
+    SkASSERT(fFlushState.nextDrawToken() == fFlushState.nextTokenToFlush());
 
     for (int i = 0; i < fDrawTargets.count(); ++i) {
         fDrawTargets[i]->reset();