check pm swizzle when extracting lcd coverage

src/core/SkXfermode4f.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPM4fPriv.h"
 #include "SkUtils.h"
 #include "SkXfermode.h"
@@ skipping 409 matching lines @@
 
 SkXfermode::PM4fProcN SkXfermode::getPM4fProcN(uint32_t flags) const {
     Mode mode;
     return this->asMode(&mode) ? GetPM4fProcN(mode, flags) : xfer_pm4_proc_n;
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 #include "SkColorPriv.h"
 
 static Sk4f lcd16_to_unit_4f(uint16_t rgb) {
+#ifdef SK_PMCOLOR_IS_RGBA
     Sk4i rgbi = Sk4i(SkGetPackedR16(rgb), SkGetPackedG16(rgb), SkGetPackedB16(rgb), 0);
+#else
+    Sk4i rgbi = Sk4i(SkGetPackedB16(rgb), SkGetPackedG16(rgb), SkGetPackedR16(rgb), 0);
+#endif
     return SkNx_cast<float>(rgbi) * Sk4f(1.0f/31, 1.0f/63, 1.0f/31, 0);
 }
 
 template <DstType D>
 void src_1_lcd(uint32_t dst[], const SkPM4f* src, int count, const uint16_t lcd[]) {
     const Sk4f s4 = Sk4f::Load(src->fVec);
     
     if (D == kLinear_Dst) {
         // operate in bias-255 space for src and dst
         const Sk4f s4bias = s4 * Sk4f(255);
@@ skipping 69 matching lines @@
 
     const LCD32Proc procs[] = {
         srcover_n_lcd<kSRGB_Dst>,   src_n_lcd<kSRGB_Dst>,
         srcover_1_lcd<kSRGB_Dst>,   src_1_lcd<kSRGB_Dst>,
 
         srcover_n_lcd<kLinear_Dst>, src_n_lcd<kLinear_Dst>,
         srcover_1_lcd<kLinear_Dst>, src_1_lcd<kLinear_Dst>,
     };
     return procs[flags];
 }