Join non-overlapping Xfer barriers

src/gpu/GrTargetCommands.h

Index: src/gpu/GrTargetCommands.h
diff --git a/src/gpu/GrTargetCommands.h b/src/gpu/GrTargetCommands.h
index 57e2971baa280d8668414964b2a52aa46c85cf98..206b626da217ec4e6ed4aed387f43ca3e8549dc9 100644
--- a/src/gpu/GrTargetCommands.h
+++ b/src/gpu/GrTargetCommands.h
@@ -33,7 +33,8 @@ public:
         : fCmdBuffer(kCmdBufferInitialSizeInBytes)
         , fPrevState(NULL)
         , fBatchTarget(gpu, vertexPool, indexPool)
-        , fDrawBatch(NULL) {
+        , fDrawBatch(NULL)
+        , fXferBarrier(NULL) {
     }
 
     class Cmd : ::SkNoncopyable {
@@ -305,14 +306,20 @@ private:
     };
 
     struct XferBarrier : public Cmd {
-        XferBarrier(GrXferBarrierType type)
+        XferBarrier(GrXferBarrierType type, GrRenderTarget* rt)
             : Cmd(kXferBarrier_CmdType)
-            , fType(type) {}
+            , fType(type)
+            , fRenderTarget(rt) {}
 
         void execute(GrGpu*, const SetState*) override;
 
         const GrXferBarrierType   fType;
-        SkIRect                   fBounds;
+        SkIRect                   fReadBounds;
+        SkIRect                   fInvalidBounds;
+
+        // The cmd buffer keeps these ptrs alive.
+        GrRenderTarget* const                      fRenderTarget;
+        SkSTArray<4, const GrXferProcessor*, true> fXferProcessors;
     };
 
      static const int kCmdBufferInitialSizeInBytes = 8 * 1024;
@@ -325,6 +332,7 @@ private:
      GrBatchTarget                       fBatchTarget;
      // TODO hack until batch is everywhere
      GrTargetCommands::DrawBatch*        fDrawBatch;
+     XferBarrier*                        fXferBarrier;
 
      // This will go away when everything uses batch.  However, in the short term anything which
      // might be put into the GrInOrderDrawBuffer needs to make sure it closes the last batch