Revert of Move DstCopy on gpu into the GrXferProcessor.

src/gpu/gl/GrGLProgramDesc.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "GrGLProgramDesc.h"
 
 #include "GrGLProcessor.h"
 #include "GrProcessor.h"
@@ skipping 71 matching lines @@
 
     uint32_t* key = b->add32n(2);
     key[0] = (textureKey << 16 | transformKey);
     key[1] = (classID << 16 | SkToU16(processorKeySize));
     return true;
 }
 
 bool GrGLProgramDescBuilder::Build(GrProgramDesc* desc,
                                    const GrPrimitiveProcessor& primProc,
                                    const GrPipeline& pipeline,
+                                   const GrProgramDesc::DescInfo& descInfo,
                                    const GrGLGpu* gpu,
                                    const GrBatchTracker& batchTracker) {
     // The descriptor is used as a cache key. Thus when a field of the
     // descriptor will not affect program generation (because of the attribute
     // bindings in use or other descriptor field settings) it should be set
     // to a canonical value to avoid duplicate programs with different keys.
 
     GR_STATIC_ASSERT(0 == kProcessorKeysOffset % sizeof(uint32_t));
     // Make room for everything up to the effect keys.
     desc->fKey.reset();
@@ skipping 25 matching lines @@
     }
 
     // --------DO NOT MOVE HEADER ABOVE THIS LINE--------------------------------------------------
     // Because header is a pointer into the dynamic array, we can't push any new data into the key
     // below here.
     KeyHeader* header = desc->atOffset<KeyHeader, kHeaderOffset>();
 
     // make sure any padding in the header is zeroed.
     memset(header, 0, kHeaderSize);
 
-    if (pipeline.readsFragPosition()) {
+    if (descInfo.fReadsDst) {
+        const GrDeviceCoordTexture* dstCopy = pipeline.getDstCopy();
+        SkASSERT(dstCopy || gpu->caps()->dstReadInShaderSupport());
+        const GrTexture* dstCopyTexture = NULL;
+        if (dstCopy) {
+            dstCopyTexture = dstCopy->texture();
+        }
+        header->fDstReadKey = GrGLFragmentShaderBuilder::KeyForDstRead(dstCopyTexture,
+                                                                       gpu->glCaps());
+        SkASSERT(0 != header->fDstReadKey);
+    } else {
+        header->fDstReadKey = 0;
+    }
+
+    if (descInfo.fReadsFragPosition) {
         header->fFragPosKey =
                 GrGLFragmentShaderBuilder::KeyForFragmentPosition(pipeline.getRenderTarget(),
                                                                   gpu->glCaps());
     } else {
         header->fFragPosKey = 0;
     }
 
     header->fColorEffectCnt = pipeline.numColorStages();
     header->fCoverageEffectCnt = pipeline.numCoverageStages();
     desc->finalize();
     return true;
 }