Add XP to handle the cases where we disable color write.

src/gpu/GrDrawState.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDrawState.h"
 
 #include "GrBlend.h"
@@ skipping 166 matching lines @@
     if (caps.dualSourceBlendingSupport()) {
         return true;
     }
 
     this->calcColorInvariantOutput(color);
 
     // The coverage isn't actually white, its unknown, but this will produce the same effect
     // TODO we want to cache the result of this call, but we can probably clean up the interface
     // so we don't have to pass in a seemingly known coverage
     this->calcCoverageInvariantOutput(GrColor_WHITE);
-    return fXPFactory->canApplyCoverage(fColorProcInfo, fCoverageProcInfo,
-                                        this->isColorWriteDisabled());
+    return fXPFactory->canApplyCoverage(fColorProcInfo, fCoverageProcInfo);
 }
 
 //////////////////////////////////////////////////////////////////////////////s
 
 bool GrDrawState::willEffectReadDstColor(const GrPrimitiveProcessor* pp) const {
     this->calcColorInvariantOutput(pp);
     this->calcCoverageInvariantOutput(pp);
-    // TODO: Remove need to create the XP here.
-    //       Also once all custom blends are turned into XPs we can remove the need
-    //       to check other stages since only xp's will be able to read dst
-    SkAutoTUnref<GrXferProcessor> xferProcessor(fXPFactory->createXferProcessor(fColorProcInfo,
-                                                                                fCoverageProcInfo));
-    if (xferProcessor && xferProcessor->willReadDstColor()) {
-        return true;
-    }
 
-    if (!this->isColorWriteDisabled()) {
-        if (fColorProcInfo.readsDst()) {
-            return true;
-        }
-    }
-    return fCoverageProcInfo.readsDst();
+    return fXPFactory->willReadDst(fColorProcInfo, fCoverageProcInfo);
 }
 
 void GrDrawState::AutoRestoreEffects::set(GrDrawState* ds) {
     if (fDrawState) {
         int m = fDrawState->numColorStages() - fColorEffectCnt;
         SkASSERT(m >= 0);
         fDrawState->fColorStages.pop_back_n(m);
 
         int n = fDrawState->numCoverageStages() - fCoverageEffectCnt;
         SkASSERT(n >= 0);
@@ skipping 113 matching lines @@
     SkASSERT(0 == fBlockEffectRemovalCnt);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 
 bool GrDrawState::willBlendWithDst(const GrPrimitiveProcessor* pp) const {
     this->calcColorInvariantOutput(pp);
     this->calcCoverageInvariantOutput(pp);
     
     GrXPFactory::InvariantOutput output;
-    fXPFactory->getInvariantOutput(fColorProcInfo, fCoverageProcInfo, this->isColorWriteDisabled(),
-                                   &output);
+    fXPFactory->getInvariantOutput(fColorProcInfo, fCoverageProcInfo, &output);
     return output.fWillBlendWithDst;
 }
 
 void GrDrawState::calcColorInvariantOutput(const GrPrimitiveProcessor* pp) const {
     if (!fColorProcInfoValid || fColorPrimProc != pp) {
         fColorProcInfo.calcColorWithPrimProc(pp, fColorStages.begin(), this->numColorStages());
         fColorProcInfoValid = true;
         fColorPrimProc = pp;
     }
 }
@@ skipping 20 matching lines @@
 void GrDrawState::calcCoverageInvariantOutput(GrColor coverage) const {
     if (!fCoverageProcInfoValid || coverage != fCoverageCache) {
         GrColorComponentFlags flags = kRGBA_GrColorComponentFlags;
         fCoverageProcInfo.calcWithInitialValues(fCoverageStages.begin(),
                                                 this->numCoverageStages(), coverage, flags,
                                                 true);
         fCoverageProcInfoValid = true;
         fCoverageCache = coverage;
     }
 }