Put clear and discard into GrBatch.

src/gpu/GrTargetCommands.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 "GrTargetCommands.h"
 
 #include "GrBatchFlushState.h"
@@ skipping 12 matching lines @@
     GrBATCH_INFO("Flushing\n");
     if (fCmdBuffer.empty()) {
         return;
     }
     GrBatchFlushState flushState(gpu, resourceProvider, fLastFlushToken);
     // Loop over all batches and generate geometry
     CmdBuffer::Iter genIter(fCmdBuffer);
     while (genIter.next()) {
         if (Cmd::kDrawBatch_CmdType == genIter->type()) {
             DrawBatch* db = reinterpret_cast<DrawBatch*>(genIter.get());
-            // TODO: encapsulate the specialization of GrVertexBatch in GrVertexBatch so that we can
-            // remove this cast. Currently all GrDrawBatches are in fact GrVertexBatch.
-            GrVertexBatch* vertexBatch = static_cast<GrVertexBatch*>(db->batch());
-
-            vertexBatch->prepareDraws(&flushState);
+            db->batch()->prepare(&flushState);
         }
     }
 
     flushState.preIssueDraws();
 
     CmdBuffer::Iter iter(fCmdBuffer);
     while (iter.next()) {
         iter->execute(&flushState);
     }
     fLastFlushToken = flushState.lastFlushedToken();
@@ skipping 22 matching lines @@
                                        *fState->getPipeline(), fState->fBatchTracker);
         fState->fCompiled = true;
     }
     GrPathRendering::DrawPathArgs args(fState->fPrimitiveProcessor.get(), fState->getPipeline(),
                                        &fState->fDesc, &fState->fBatchTracker, &fStencilSettings);
     state->gpu()->pathRendering()->drawPaths(args, this->pathRange(), fIndices, fIndexType,
                                              fTransforms, fTransformType, fCount);
 }
 
 void GrTargetCommands::DrawBatch::execute(GrBatchFlushState* state) {
-    // TODO: encapsulate the specialization of GrVertexBatch in GrVertexBatch so that we can
-    // remove this cast. Currently all GrDrawBatches are in fact GrVertexBatch.
-    GrVertexBatch* vertexBatch = static_cast<GrVertexBatch*>(fBatch.get());
-    vertexBatch->issueDraws(state);
-}
-
-
-void GrTargetCommands::Clear::execute(GrBatchFlushState* state) {
-    if (GrColor_ILLEGAL == fColor) {
-        state->gpu()->discard(this->renderTarget());
-    } else {
-        state->gpu()->clear(fRect, fColor, this->renderTarget());
-    }
+    fBatch->draw(state);
 }
 
 void GrTargetCommands::ClearStencilClip::execute(GrBatchFlushState* state) {
     state->gpu()->clearStencilClip(fRect, fInsideClip, this->renderTarget());
 }
 
 void GrTargetCommands::CopySurface::execute(GrBatchFlushState* state) {
     state->gpu()->copySurface(this->dst(), this->src(), fSrcRect, fDstPoint);
 }