Make skpaint->grpaint flow work for composing draws

src/core/SkDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorFilter.h"
 #include "SkDevice.h"
 #include "SkDraw.h"
@@ skipping 186 matching lines @@
 
         SkPaint pnt(paint);
         SkAutoTUnref<SkShader> shader(atlas->newShader(SkShader::kClamp_TileMode,
                                                        SkShader::kClamp_TileMode,
                                                        &localM));
         if (!shader) {
             break;
         }
         pnt.setShader(shader);
 
-        if (colors && colors[i] != SK_ColorWHITE) {
+        if (colors) {
             SkAutoTUnref<SkColorFilter> cf(SkColorFilter::CreateModeFilter(colors[i], mode));
             pnt.setColorFilter(cf);
         }
         
         path.rewind();
         path.addPoly(quad, 4, true);
         path.setConvexity(SkPath::kConvex_Convexity);
         this->drawPath(draw, path, pnt, nullptr, true);
     }
 }
@@ skipping 194 matching lines @@
     if (kUnknown_SkPixelGeometry == fSurfaceProps.pixelGeometry()
         || this->onShouldDisableLCD(paint)) {
 
         flags &= ~SkPaint::kLCDRenderText_Flag;
         flags |= SkPaint::kGenA8FromLCD_Flag;
     }
 
     return flags;
 }