Restructure flushing relationship between GrContext, GrDrawingManager, and GrResourceCache.

src/gpu/GrDrawContext.cpp

Index: src/gpu/GrDrawContext.cpp
diff --git a/src/gpu/GrDrawContext.cpp b/src/gpu/GrDrawContext.cpp
index 87252f39792ab174a2d62bb2ca127a81a9c8fd58..ed02602499d1d027bef67136275f3644775e8421 100644
--- a/src/gpu/GrDrawContext.cpp
+++ b/src/gpu/GrDrawContext.cpp
@@ -59,7 +59,7 @@ public:
     AutoCheckFlush(GrDrawingManager* drawingManager) : fDrawingManager(drawingManager) {
         SkASSERT(fDrawingManager);
     }
-    ~AutoCheckFlush() { fDrawingManager->getContext()->flushIfNecessary(); }
+    ~AutoCheckFlush() { fDrawingManager->flushIfNecessary(); }
 
 private:
     GrDrawingManager* fDrawingManager;