Refactoring of GPU NormalMap handling out into its own class.

The purpose of this change is to refactor the handling of normal maps out of SkLightingShader, laying the groundwork to eventually allow for multiple normal sources.

What this CL includes:

- Created a new 'NormalMapFP', out of the existing normal map reading behavior in LightingFP.

- Encapsulates this new fragment processor on a new class NormalMapSource.

- Created a NormalSource abstraction that will interface with SkLightingShader.

- Adapted SkLightingShader to use the normals from its NormalSource field ON THE GPU SIDE. No changes done to the CPU side yet.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2043393002

Review-Url: https://codereview.chromium.org/2043393002

1 files changed, 1 insertions, 0 deletions

diff --git a/include/core/SkFlattenable.h b/include/core/SkFlattenable.h
index 260ea33dab..5eabcb3d6d 100644
--- a/include/core/SkFlattenable.h
+++ b/include/core/SkFlattenable.h
@@ -81,6 +81,7 @@ public:
         kSkShader_Type,
         kSkUnused_Type,     // used to be SkUnitMapper
         kSkXfermode_Type,
+        kNormalSource_Type,
     };
 
     typedef sk_sp<SkFlattenable> (*Factory)(SkReadBuffer&);