Revert of Revert of make gm background colors 565 compatible

tools/sk_tool_utils.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "sk_tool_utils.h"
 #include "sk_tool_utils_flags.h"
 
@@ skipping 16 matching lines @@
         case kARGB_4444_SkColorType:    return "ARGB_4444";
         case kRGB_565_SkColorType:      return "RGB_565";
         case kRGBA_8888_SkColorType:    return "RGBA_8888";
         case kBGRA_8888_SkColorType:    return "BGRA_8888";
         default:
             SkASSERT(false);
             return "unexpected colortype";
     }
 }
 
-void color_to_565(SkColor* color) {
-    SkPMColor pmColor = SkPreMultiplyColor(*color);
+SkColor color_to_565(SkColor color) {
+    SkPMColor pmColor = SkPreMultiplyColor(color);
     U16CPU color16 = SkPixel32ToPixel16(pmColor);
-    *color = SkPixel16ToColor(color16);
+    return SkPixel16ToColor(color16);
 }
 
 SkTypeface* create_portable_typeface(const char* name, SkTypeface::Style style) {
     SkTypeface* face;
     if (FLAGS_portableFonts) {
         face = create_font(name, style);
     } else if (FLAGS_resourceFonts) {
         face = resource_font(name, style);
     } else {
         face = SkTypeface::CreateFromName(name, style);
@@ skipping 52 matching lines @@
     paint.textToGlyphs(text, len, glyphs.begin());
 
     paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
     const SkTextBlobBuilder::RunBuffer& run = builder->allocRun(paint, glyphs.count(), x, y,
                                                                 NULL);
     memcpy(run.glyphs, glyphs.begin(), glyphs.count() * sizeof(uint16_t));
 }
 
 
 }  // namespace sk_tool_utils