Add "sample locations" feature to GrProcessor

src/gpu/vk/GrVkProgramDesc.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 "GrVkProgramDesc.h"
 
 //#include "GrVkProcessor.h"
 #include "GrProcessor.h"
@@ skipping 116 matching lines @@
     requiredFeatures |= xp.requiredFeatures();
 
     // --------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 = vkDesc->atOffset<KeyHeader, kHeaderOffset>();
 
     // make sure any padding in the header is zeroed.
     memset(header, 0, kHeaderSize);
 
+    GrRenderTarget* rt = pipeline.getRenderTarget();
+
     if (requiredFeatures & GrProcessor::kFragmentPosition_RequiredFeature) {
-        header->fFragPosKey =
-            GrGLSLFragmentShaderBuilder::KeyForFragmentPosition(pipeline.getRenderTarget());
+        header->fFragPosKey = GrGLSLFragmentShaderBuilder::KeyForFragmentPosition(rt);
     } else {
         header->fFragPosKey = 0;
     }
 
-    header->fOutputSwizzle =
-        glslCaps.configOutputSwizzle(pipeline.getRenderTarget()->config()).asKey();
+    header->fOutputSwizzle = glslCaps.configOutputSwizzle(rt->config()).asKey();
 
     if (pipeline.ignoresCoverage()) {
         header->fIgnoresCoverage = 1;
     } else {
         header->fIgnoresCoverage = 0;
     }
 
     header->fSnapVerticesToPixelCenters = pipeline.snapVerticesToPixelCenters();
     header->fColorEffectCnt = pipeline.numColorFragmentProcessors();
     header->fCoverageEffectCnt = pipeline.numCoverageFragmentProcessors();
+
+    if (requiredFeatures & GrProcessor::kSampleLocations_RequiredFeature) {
+        SkASSERT(pipeline.isHWAntialiasState());
+        header->fSamplePatternKey =
+            rt->renderTargetPriv().getSamplePatternID(pipeline.getStencil());
+    } else {
+        header->fSamplePatternKey = 0;
+    }
+
     vkDesc->finalize();
     return true;
 }