Revert of Make all blending up to GrOptDrawState be handled by the xp/xp factory.

src/gpu/GrPaint.cpp

Index: src/gpu/GrPaint.cpp
diff --git a/src/gpu/GrPaint.cpp b/src/gpu/GrPaint.cpp
index 5ed573a88bbb0906a4dd8d4ea210368f672d6b39..443e1c0abf71a1e81471956989b9626f3cfe2980 100644
--- a/src/gpu/GrPaint.cpp
+++ b/src/gpu/GrPaint.cpp
@@ -8,6 +8,7 @@
 
 #include "GrPaint.h"
 
+#include "GrBlend.h"
 #include "GrProcOptInfo.h"
 #include "effects/GrPorterDuffXferProcessor.h"
 #include "effects/GrSimpleTextureEffect.h"
@@ -51,20 +52,73 @@
 void GrPaint::resetStages() {
     fColorStages.reset();
     fCoverageStages.reset();
-    fXPFactory.reset(GrPorterDuffXPFactory::Create(SkXfermode::kSrc_Mode));
+    fXPFactory.reset(GrPorterDuffXPFactory::Create(SkXfermode::kSrcOver_Mode));
 }
 
 bool GrPaint::getOpaqueAndKnownColor(GrColor* solidColor,
                                      uint32_t* solidColorKnownComponents) const {
 
+    // TODO: Share this implementation with GrDrawState
+    
     GrProcOptInfo coverageProcInfo;
     coverageProcInfo.calcWithInitialValues(fCoverageStages.begin(), this->numCoverageStages(),
                                            0xFFFFFFFF, kRGBA_GrColorComponentFlags, true);
+
+    if (!coverageProcInfo.isSolidWhite()) {
+        return false;
+    }
+
     GrProcOptInfo colorProcInfo;
     colorProcInfo.calcWithInitialValues(fColorStages.begin(), this->numColorStages(), fColor,
                                         kRGBA_GrColorComponentFlags, false);
 
-    return fXPFactory->getOpaqueAndKnownColor(colorProcInfo, coverageProcInfo, solidColor,
-                                              solidColorKnownComponents);
+    SkASSERT((NULL == solidColor) == (NULL == solidColorKnownComponents));
+
+    GrBlendCoeff srcCoeff = fSrcBlendCoeff;
+    GrBlendCoeff dstCoeff = fDstBlendCoeff;
+    GrSimplifyBlend(&srcCoeff, &dstCoeff, colorProcInfo.color(), colorProcInfo.validFlags(),
+                    0, 0, 0);
+
+    bool opaque = kZero_GrBlendCoeff == dstCoeff && !GrBlendCoeffRefsDst(srcCoeff);
+    if (solidColor) {
+        if (opaque) {
+            switch (srcCoeff) {
+                case kZero_GrBlendCoeff:
+                    *solidColor = 0;
+                    *solidColorKnownComponents = kRGBA_GrColorComponentFlags;
+                    break;
+
+                case kOne_GrBlendCoeff:
+                    *solidColor = colorProcInfo.color();
+                    *solidColorKnownComponents = colorProcInfo.validFlags();
+                    break;
+
+                // The src coeff should never refer to the src and if it refers to dst then opaque
+                // should have been false.
+                case kSC_GrBlendCoeff:
+                case kISC_GrBlendCoeff:
+                case kDC_GrBlendCoeff:
+                case kIDC_GrBlendCoeff:
+                case kSA_GrBlendCoeff:
+                case kISA_GrBlendCoeff:
+                case kDA_GrBlendCoeff:
+                case kIDA_GrBlendCoeff:
+                default:
+                    SkFAIL("srcCoeff should not refer to src or dst.");
+                    break;
+
+                // TODO: update this once GrPaint actually has a const color.
+                case kConstC_GrBlendCoeff:
+                case kIConstC_GrBlendCoeff:
+                case kConstA_GrBlendCoeff:
+                case kIConstA_GrBlendCoeff:
+                    *solidColorKnownComponents = 0;
+                    break;
+            }
+        } else {
+            solidColorKnownComponents = 0;
+        }
+    }
+    return opaque;
 }