remove U16 support, just support F16

src/core/SkBlitter.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBlitter.h"
 #include "SkAntiRun.h"
 #include "SkColor.h"
@@ skipping 920 matching lines @@
                     blitter = allocator->createT<SkARGB32_Black_Blitter>(device, *paint);
                 } else if (paint->getAlpha() == 0xFF) {
                     blitter = allocator->createT<SkARGB32_Opaque_Blitter>(device, *paint);
                 } else {
                     blitter = allocator->createT<SkARGB32_Blitter>(device, *paint);
                 }
             }
             break;
 
         case kRGBA_F16_SkColorType:
-        // kU16_SkColorType:
-            blitter = SkBlitter_ARGB64_Create(device, *paint, shaderContext, allocator);
+            blitter = SkBlitter_F16_Create(device, *paint, shaderContext, allocator);
             break;
 
         default:
             break;
     }
 
     if (!blitter) {
         blitter = allocator->createT<SkNullBlitter>();
     }
 
@@ skipping 50 matching lines @@
     fShaderContext->~Context();
     SkShader::Context* ctx = fShader->createContext(rec, (void*)fShaderContext);
     if (nullptr == ctx) {
         // Need a valid context in fShaderContext's storage, so we can later (or our caller) call
         // the in-place destructor.
         new (fShaderContext) SkZeroShaderContext(*fShader, rec);
         return false;
     }
     return true;
 }