Reland "Revert "added GrSkSLFP and converted DitherEffect to use it""

This reverts commit 97ae0c89025dfd791047f5701e57d58da37c125c.

Reason for revert: Breaking ANGLE.

Original change's description:
> Revert "Revert "added GrSkSLFP and converted DitherEffect to use it""
> 
> This reverts commit f2030783094e502fb74221077a5ee7cb41287fe4.
> 
> Bug: skia:
> Change-Id: Icaaa8b3ea652a8f126bfbcc788a360493a7ebe3e
> Reviewed-on: https://skia-review.googlesource.com/137391
> Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

TBR=bsalomon@google.com,robertphillips@google.com,ethannicholas@google.com

Change-Id: I65d6d2707fceab0a99121c528d1b848d23e34bfa
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/142588
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>

1 files changed, 2 insertions, 19 deletions

diff --git a/src/sksl/ir/SkSLAppendStage.h b/src/sksl/ir/SkSLAppendStage.h
index 268ae979d2..87a8210a83 100644
--- a/src/sksl/ir/SkSLAppendStage.h
+++ b/src/sksl/ir/SkSLAppendStage.h
@@ -23,16 +23,7 @@ struct AppendStage : public Expression {
     , fStage(stage)
     , fArguments(std::move(arguments)) {}
 
-    std::unique_ptr<Expression> clone() const override {
-        std::vector<std::unique_ptr<Expression>> cloned;
-        for (const auto& arg : fArguments) {
-            cloned.push_back(arg->clone());
-        }
-        return std::unique_ptr<Expression>(new AppendStage(fOffset, fStage, std::move(cloned),
-                                                           &fType));
-    }
-
-    String description() const override {
+    String description() const {
         String result = "append(";
         const char* separator = "";
         for (const auto& a : fArguments) {
@@ -44,7 +35,7 @@ struct AppendStage : public Expression {
         return result;
     }
 
-    bool hasSideEffects() const override {
+    bool hasSideEffects() const {
         return true;
     }
 
@@ -53,14 +44,6 @@ struct AppendStage : public Expression {
     std::vector<std::unique_ptr<Expression>> fArguments;
 
     typedef Expression INHERITED;
-
-private:
-    AppendStage(int offset, SkRasterPipeline::StockStage stage,
-                std::vector<std::unique_ptr<Expression>> arguments, const Type* type)
-    : INHERITED(offset, kAppendStage_Kind, *type)
-    , fStage(stage)
-    , fArguments(std::move(arguments)) {}
-
 };
 
 } // namespace