Remove support for inheriting the paint color from SkColorShader

tests/ShaderOpacityTest.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 "SkColorShader.h"
 #include "SkGradientShader.h"
 #include "SkShader.h"
@@ skipping 85 matching lines @@
 }
 
 static void test_color(skiatest::Reporter* reporter)
 {
     SkColorShader colorShader1(SkColorSetARGB(0,0,0,0));
     REPORTER_ASSERT(reporter, !colorShader1.isOpaque());
     SkColorShader colorShader2(SkColorSetARGB(0xFF,0,0,0));
     REPORTER_ASSERT(reporter, colorShader2.isOpaque());
     SkColorShader colorShader3(SkColorSetARGB(0x7F,0,0,0));
     REPORTER_ASSERT(reporter, !colorShader3.isOpaque());
-
-    // with inherrited color, shader must declare itself as opaque,
-    // since lack of opacity will depend solely on the paint
-    SkColorShader colorShader4;
-    REPORTER_ASSERT(reporter, colorShader4.isOpaque());
 }
 
 DEF_TEST(ShaderOpacity, reporter) {
     test_gradient(reporter);
     test_color(reporter);
     test_bitmap(reporter);
 }