Dependencies are now added between the drawTargets in GrPipeline

src/gpu/GrDrawTarget.h

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDrawTarget_DEFINED
 #define GrDrawTarget_DEFINED
 
@@ skipping 15 matching lines @@
 #include "SkClipStack.h"
 #include "SkMatrix.h"
 #include "SkPath.h"
 #include "SkStringUtils.h"
 #include "SkStrokeRec.h"
 #include "SkTArray.h"
 #include "SkTLazy.h"
 #include "SkTypes.h"
 #include "SkXfermode.h"
 
+//#define ENABLE_MDB 1
+
 class GrBatch;
 class GrBatchFlushState;
 class GrClip;
 class GrCaps;
 class GrPath;
 class GrDrawPathBatchBase;
 class GrPathRangeDraw;
 
 class GrDrawTarget final : public SkRefCnt {
 public:
     struct Options {
         bool fImmediateMode;
     };
 
     // The context may not be fully constructed and should not be used during GrDrawTarget
     // construction.
-    GrDrawTarget(GrGpu* gpu, GrResourceProvider*, const Options& options);
+    GrDrawTarget(GrRenderTarget* rt, GrGpu* gpu, GrResourceProvider*, const Options& options);
 
     ~GrDrawTarget() override;
 
     void makeClosed() {
         // We only close drawTargets When MDB is enabled. When MDB is disabled there is only
         // ever one drawTarget and all calls will be funnelled into it.
 #ifdef ENABLE_MDB
         this->setFlag(kClosed_Flag);
 #endif
     }
     bool isClosed() const { return this->isSetFlag(kClosed_Flag); }
 
+    // TODO: this entry point is only needed in the non-MDB world. Remove when
+    // we make the switch to MDB
+    void clearRT() { fRenderTarget = nullptr; }
+
     /*
      * Notify this drawTarget that it relies on the contents of 'dependedOn'
      */
     void addDependency(GrSurface* dependedOn);
 
     /*
      * Does this drawTarget depend on 'dependedOn'?
      */
     bool dependsOn(GrDrawTarget* dependedOn) const {
         return fDependencies.find(dependedOn) >= 0;
@@ skipping 236 matching lines @@
     GrBatchFlushState                           fFlushState;
     bool                                        fFlushing;
     int                                         fFirstUnpreparedBatch;
 
     SkDEBUGCODE(int                             fDebugID;)
     uint32_t                                    fFlags;
     Options                                     fOptions;
 
     // 'this' drawTarget relies on the output of the drawTargets in 'fDependencies'
     SkTDArray<GrDrawTarget*>                    fDependencies;
+    GrRenderTarget*                             fRenderTarget;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif