Add direct getter for GrCaps to GrContext.

src/gpu/GrAtlasTextContext.cpp

Index: src/gpu/GrAtlasTextContext.cpp
diff --git a/src/gpu/GrAtlasTextContext.cpp b/src/gpu/GrAtlasTextContext.cpp
index 14f8ef71064c85f8e22b0f51333c0850bae24e05..f92547edea35c966ad7812de2a0d7c63b4f4e65e 100644
--- a/src/gpu/GrAtlasTextContext.cpp
+++ b/src/gpu/GrAtlasTextContext.cpp
@@ -460,7 +460,7 @@ inline bool GrAtlasTextContext::canDrawAsDistanceFields(const SkPaint& skPaint,
     // rasterizers and mask filters modify alpha, which doesn't
     // translate well to distance
     if (skPaint.getRasterizer() || skPaint.getMaskFilter() ||
-        !fContext->shaderDerivativeSupport()) {
+        !fContext->caps()->shaderCaps()->shaderDerivativeSupport()) {
         return false;
     }