Restructure flushing relationship between GrContext, GrDrawingManager, and GrResourceCache.

src/gpu/GrDrawContext.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBatchTest.h"
 #include "GrColor.h"
 #include "GrDrawContext.h"
@@ skipping 41 matching lines @@
 #define RETURN_FALSE_IF_ABANDONED_PRIV  if (fDrawContext->fDrawingManager->wasAbandoned()) { return false; }
 #define RETURN_NULL_IF_ABANDONED   if (fDrawingManager->wasAbandoned()) { return nullptr; }
 
 using gr_instanced::InstancedRendering;
 
 class AutoCheckFlush {
 public:
     AutoCheckFlush(GrDrawingManager* drawingManager) : fDrawingManager(drawingManager) {
         SkASSERT(fDrawingManager);
     }
-    ~AutoCheckFlush() { fDrawingManager->getContext()->flushIfNecessary(); }
+    ~AutoCheckFlush() { fDrawingManager->flushIfNecessary(); }
 
 private:
     GrDrawingManager* fDrawingManager;
 };
 
 bool GrDrawContext::wasAbandoned() const {
     return fDrawingManager->wasAbandoned();
 }
 
 // In MDB mode the reffing of the 'getLastDrawTarget' call's result allows in-progress
@@ skipping 1355 matching lines @@
 
 void GrDrawContext::drawBatch(const GrPipelineBuilder& pipelineBuilder, const GrClip& clip,
                               GrDrawBatch* batch) {
     ASSERT_SINGLE_OWNER
     RETURN_IF_ABANDONED
     SkDEBUGCODE(this->validate();)
     GR_AUDIT_TRAIL_AUTO_FRAME(fAuditTrail, "GrDrawContext::drawBatch");
 
     this->getDrawTarget()->drawBatch(pipelineBuilder, this, clip, batch);
 }