Update SkLightingShader to take a localMatrix

W/o this we can't draw lit objects anywhere but the origin.

Review URL: https://codereview.chromium.org/1253223003
diff --git a/samplecode/SampleLighting.cpp b/samplecode/SampleLighting.cpp
index 079cb68..3cda0c6 100755
--- a/samplecode/SampleLighting.cpp
+++ b/samplecode/SampleLighting.cpp
@@ -41,7 +41,7 @@
         fAmbientColor = SkColorSetRGB(0x1f, 0x1f, 0x1f);
 
         fShader.reset(SkLightingShader::Create(fDiffuseBitmap, fNormalBitmap,
-                                               light, fAmbientColor));
+                                               light, fAmbientColor, nullptr));
     }
 
     virtual ~LightingView() {}
@@ -67,7 +67,7 @@
         light.fDirection.fZ = SkScalarCos(SK_ScalarPI*0.25f);
 
         fShader.reset(SkLightingShader::Create(fDiffuseBitmap, fNormalBitmap,
-                                               light, fAmbientColor));
+                                               light, fAmbientColor, nullptr));
 
         SkPaint paint;
         paint.setShader(fShader);