add blitprocs to shaders

src/core/SkShader.cpp

Index: src/core/SkShader.cpp
diff --git a/src/core/SkShader.cpp b/src/core/SkShader.cpp
index 1413a6ee7336aecd60762c71c11889def7f7c04d..cb0517bf64073e43389e4b4868a9ffeeaf253237 100644
--- a/src/core/SkShader.cpp
+++ b/src/core/SkShader.cpp
@@ -361,6 +361,46 @@ void SkColorShader::toString(SkString* str) const {
 
 ///////////////////////////////////////////////////////////////////////////////
 
+static void D32_BlitProc(SkShader::Context::BlitState* state, int x, int y, const SkPixmap& dst,
+                         int count, const SkAlpha aa[]) {
+    SkXfermode::D32Proc proc = (SkXfermode::D32Proc)state->fStorage[0];
+    const SkPM4f* src = (const SkPM4f*)state->fStorage[1];
+    proc(state->fXfer, dst.writable_addr32(x, y), src, count, aa);
+}
+
+static void D64_BlitProc(SkShader::Context::BlitState* state, int x, int y, const SkPixmap& dst,
+                         int count, const SkAlpha aa[]) {
+    SkXfermode::D64Proc proc = (SkXfermode::D64Proc)state->fStorage[0];
+    const SkPM4f* src = (const SkPM4f*)state->fStorage[1];
+    proc(state->fXfer, dst.writable_addr64(x, y), src, count, aa);
+}
+
+SkShader::Context::BlitProc
+SkColorShader::ColorShaderContext::onChooseBlitProc(const SkImageInfo& info, BlitState* state) {
+    uint32_t flags = SkXfermode::kSrcIsSingle_D32Flag;
+    if (fPM4f.a() == 1) {
+        flags |= SkXfermode::kSrcIsOpaque_D32Flag;
+    }
+    switch (info.colorType()) {
+        case kN32_SkColorType:
+            if (info.isSRGB()) {
+                flags |= SkXfermode::kDstIsSRGB_D32Flag;
+            }
+            state->fStorage[0] = (void*)SkXfermode::GetD32Proc(state->fXfer, flags);
+            state->fStorage[1] = &fPM4f;
+            return D32_BlitProc;
+        case kRGBA_F16_SkColorType:
+            flags |= SkXfermode::kDstIsFloat16_D64Flag;
+            state->fStorage[0] = (void*)SkXfermode::GetD64Proc(state->fXfer, flags);
+            state->fStorage[1] = &fPM4f;
+            return D64_BlitProc;
+        default:
+            return nullptr;
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
 SkFlattenable* SkEmptyShader::CreateProc(SkReadBuffer&) {
     return SkShader::MakeEmptyShader().release();
 }