Make SkBlitter hierarchy explicit about what needs to be implemented.

tests/FillPathTest.cpp

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBlitter.h"
 #include "SkPath.h"
 #include "SkRegion.h"
 #include "SkScan.h"
 #include "Test.h"
 
 struct FakeBlitter : public SkBlitter {
-  FakeBlitter()
-      : m_blitCount(0)
-  {}
+    FakeBlitter()
+        : m_blitCount(0) { }
 
-  virtual void blitH(int x, int y, int width) {
-    m_blitCount++;
-  }
+    void blitH(int x, int y, int width) override {
+        m_blitCount++;
+    }
 
-  int m_blitCount;
+    void blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[]) override {
+      SkDEBUGFAIL("blitAntiH not implemented");
+    }
+
+    int m_blitCount;
 };
 
 // http://code.google.com/p/skia/issues/detail?id=87
 // Lines which is not clipped by boundary based clipping,
 // but skipped after tessellation, should be cleared by the blitter.
 DEF_TEST(FillPathInverse, reporter) {
-  FakeBlitter blitter;
-  SkIRect clip;
-  SkPath path;
-  int height = 100;
-  int width  = 200;
-  int expected_lines = 5;
-  clip.set(0, height - expected_lines, width, height);
-  path.moveTo(0.0f, 0.0f);
-  path.quadTo(SkIntToScalar(width/2), SkIntToScalar(height),
+    FakeBlitter blitter;
+    SkIRect clip;
+    SkPath path;
+    int height = 100;
+    int width  = 200;
+    int expected_lines = 5;
+    clip.set(0, height - expected_lines, width, height);
+    path.moveTo(0.0f, 0.0f);
+    path.quadTo(SkIntToScalar(width/2), SkIntToScalar(height),
               SkIntToScalar(width), 0.0f);
-  path.close();
-  path.setFillType(SkPath::kInverseWinding_FillType);
-  SkScan::FillPath(path, clip, &blitter);
+    path.close();
+    path.setFillType(SkPath::kInverseWinding_FillType);
+    SkScan::FillPath(path, clip, &blitter);
 
-  REPORTER_ASSERT(reporter, blitter.m_blitCount == expected_lines);
+    REPORTER_ASSERT(reporter, blitter.m_blitCount == expected_lines);
 }