Create GrDraw and start fast pathing src over rects

src/gpu/batches/GrTInstanceBatch.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrTInstanceBatch_DEFINED
 #define GrTInstanceBatch_DEFINED
 
@@ skipping 59 matching lines @@
     void init() {
         const Geometry& geo = fGeoData[0];
         Impl::SetBounds(geo, &fBounds);
     }
 
     void updateBoundsAfterAppend() {
         const Geometry& geo = fGeoData.back();
         Impl::UpdateBoundsAfterAppend(geo, &fBounds);
     }
 
+    bool appendIfPossible(const Geometry& geo) {
+        const Geometry& mine = fGeoData.back();
+        if (Impl::CanCombine(mine, geo, fOpts)) {
+            fGeoData.push_back(geo);
+            this->updateBoundsAfterAppend();
+            return true;
+        } else {
+            return false;
+        }
+
+    }
+
 private:
     GrTInstanceBatch() : INHERITED(ClassID()) {}
 
     void onPrepareDraws(Target* target) override {
         SkAutoTUnref<const GrGeometryProcessor> gp(Impl::CreateGP(this->seedGeometry(), fOpts));
         if (!gp) {
             SkDebugf("Couldn't create GrGeometryProcessor\n");
             return;
         }
 
@@ skipping 45 matching lines @@
         return true;
     }
 
     GrPipelineOptimizations fOpts;
     SkSTArray<1, Geometry, true> fGeoData;
 
     typedef GrVertexBatch INHERITED;
 };
 
 #endif