add new blit2 methods in support of antialiased hairlines

before:
   9M	1	528µs	530µs	539µs	607µs	5%	▁▁▁▁▁▁▁▁█▂	8888	path_hairline_small_AA_quad

after:
   9M	1	355µs	356µs	358µs	375µs	2%	▂▁▁▁▁▁▁▁▁█	8888	path_hairline_small_AA_quad

BUG=skia:

does require new baselines (bug chrome is guarded)

Review URL: https://codereview.chromium.org/1060153003

1 files changed, 35 insertions, 2 deletions

diff --git a/src/core/SkBlitter.h b/src/core/SkBlitter.h
index 9447bf1b51..51d60a4576 100644
--- a/src/core/SkBlitter.h
+++ b/src/core/SkBlitter.h
@@ -1,4 +1,3 @@
-
 /*
  * Copyright 2006 The Android Open Source Project
  *
@@ -6,10 +5,15 @@
  * found in the LICENSE file.
  */
 
-
 #ifndef SkBlitter_DEFINED
 #define SkBlitter_DEFINED
 
+#ifdef SK_SUPPORT_LEGACY_BLITANTIH2V2
+    #define SK_BLITANTIH2V2_VIRTUAL
+#else
+    #define SK_BLITANTIH2V2_VIRTUAL virtual
+#endif
+
 #include "SkBitmap.h"
 #include "SkBitmapProcShader.h"
 #include "SkMask.h"
@@ -55,6 +59,35 @@ public:
     */
     virtual const SkBitmap* justAnOpaqueColor(uint32_t* value);
 
+    // (x, y), (x + 1, y)
+    SK_BLITANTIH2V2_VIRTUAL void blitAntiH2(int x, int y, U8CPU a0, U8CPU a1) {
+        int16_t runs[3];
+        uint8_t  aa[2];
+        
+        runs[0] = 1;
+        runs[1] = 1;
+        runs[2] = 0;
+        aa[0] = SkToU8(a0);
+        aa[1] = SkToU8(a1);
+        this->blitAntiH(x, y, aa, runs);
+    }
+
+    // (x, y), (x, y + 1)
+    SK_BLITANTIH2V2_VIRTUAL void blitAntiV2(int x, int y, U8CPU a0, U8CPU a1) {
+        int16_t runs[2];
+        uint8_t  aa[1];
+        
+        runs[0] = 1;
+        runs[1] = 0;
+        aa[0] = SkToU8(a0);
+        this->blitAntiH(x, y, aa, runs);
+        // reset in case the clipping blitter modified runs
+        runs[0] = 1;
+        runs[1] = 0;
+        aa[0] = SkToU8(a1);
+        this->blitAntiH(x, y + 1, aa, runs);
+    }
+    
     /**
      *  Special method just to identify the null blitter, which is returned
      *  from Choose() if the request cannot be fulfilled. Default impl