Refactor read and write buffers.

src/effects/gradients/SkTwoPointConicalGradient.cpp

Index: src/effects/gradients/SkTwoPointConicalGradient.cpp
diff --git a/src/effects/gradients/SkTwoPointConicalGradient.cpp b/src/effects/gradients/SkTwoPointConicalGradient.cpp
index a9bd1c276274f1ba952f8fd544e6fefb1f6f6190..6a503d2fb7bea439af3876228ca07a8cf79e7b4d 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient.cpp
+++ b/src/effects/gradients/SkTwoPointConicalGradient.cpp
@@ -310,7 +310,7 @@ SkShader::GradientType SkTwoPointConicalGradient::asAGradient(
 }
 
 SkTwoPointConicalGradient::SkTwoPointConicalGradient(
-    SkFlattenableReadBuffer& buffer)
+    SkReadBuffer& buffer)
     : INHERITED(buffer),
     fCenter1(buffer.readPoint()),
     fCenter2(buffer.readPoint()),
@@ -320,7 +320,7 @@ SkTwoPointConicalGradient::SkTwoPointConicalGradient(
 };
 
 void SkTwoPointConicalGradient::flatten(
-    SkFlattenableWriteBuffer& buffer) const {
+    SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writePoint(fCenter1);
     buffer.writePoint(fCenter2);