Revert of Turned on SkSL->GLSL compiler (patchset #49 id:1240001 of https://codereview.chromium.org/2288033003/ )

Reason for revert:
Pre-emptive revert. Sorry, but we're getting back up on our roll and Chrome reverted our last one for apparently no reason.

Original issue's description:
> Turned on SkSL->GLSL compiler
> GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2288033003
>
> Committed: https://skia.googlesource.com/skia/+/9b0fe3d125f237d9884732a48414fa85fc71b4e3
> Committed: https://skia.googlesource.com/skia/+/b12b3c6908c62c908b3680be01e3b5bfd30de310
> Committed: https://skia.googlesource.com/skia/+/f008b0a59f45c0d4bea3e66faf3b01805009ec89
> Committed: https://skia.googlesource.com/skia/+/08b2ccf398e2b81bc05d2c105837e5419899469b
> Committed: https://skia.googlesource.com/skia/+/dcfe6dba4a335e50e86ff68e3252065d4197432c
> Committed: https://skia.googlesource.com/skia/+/ccb1dd8f267f9d7fe7c9d0ce222ebc81b41853b3

TBR=benjaminwagner@google.com,bsalomon@google.com,egdaniel@google.com,ethannicholas@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review-Url: https://codereview.chromium.org/2408193002

5 files changed, 6 insertions, 113 deletions

diff --git a/src/sksl/ast/SkSLASTDeclaration.h b/src/sksl/ast/SkSLASTDeclaration.h
index 70f0ebc72d..8b55ecf832 100644
--- a/src/sksl/ast/SkSLASTDeclaration.h
+++ b/src/sksl/ast/SkSLASTDeclaration.h
@@ -20,9 +20,7 @@ struct ASTDeclaration : public ASTPositionNode {
         kVar_Kind,
         kFunction_Kind,
         kInterfaceBlock_Kind,
-        kExtension_Kind,
-        kPrecision_Kind,
-        kModifiers_Kind
+        kExtension_Kind
     };
 
     ASTDeclaration(Position position, Kind kind)
diff --git a/src/sksl/ast/SkSLASTIndexSuffix.h b/src/sksl/ast/SkSLASTIndexSuffix.h
index 755029b0a2..44d91fa4c4 100644
--- a/src/sksl/ast/SkSLASTIndexSuffix.h
+++ b/src/sksl/ast/SkSLASTIndexSuffix.h
@@ -14,27 +14,17 @@
 namespace SkSL {
 
 /**
- * A bracketed expression, as in '[0]', indicating an array access. Empty brackets (as occur in
- * 'float[](5, 6)' are represented with a null fExpression.
+ * A bracketed expression, as in '[0]', indicating an array access. 
  */
 struct ASTIndexSuffix : public ASTSuffix {
-    ASTIndexSuffix(Position position) 
-    : INHERITED(position, ASTSuffix::kIndex_Kind)
-    , fExpression(nullptr) {}
-
     ASTIndexSuffix(std::unique_ptr<ASTExpression> expression) 
-    : INHERITED(expression ? expression->fPosition : Position(), ASTSuffix::kIndex_Kind)
+    : INHERITED(expression->fPosition, ASTSuffix::kIndex_Kind)
     , fExpression(std::move(expression)) {}
 
     std::string description() const override {
-        if (fExpression) {
-            return "[" + fExpression->description() + "]";
-        } else {
-            return "[]";
-        }
+        return "[" + fExpression->description() + "]";
     }
 
-    // may be null
     std::unique_ptr<ASTExpression> fExpression;
 
     typedef ASTSuffix INHERITED;
diff --git a/src/sksl/ast/SkSLASTLayout.h b/src/sksl/ast/SkSLASTLayout.h
index 515eb2bdbb..08d67531c3 100644
--- a/src/sksl/ast/SkSLASTLayout.h
+++ b/src/sksl/ast/SkSLASTLayout.h
@@ -20,16 +20,13 @@ namespace SkSL {
  */
 struct ASTLayout : public ASTNode {
     // For all parameters, a -1 means no value
-    ASTLayout(int location, int binding, int index, int set, int builtin, bool originUpperLeft,
-              bool overrideCoverage, bool blendSupportAllEquations)
+    ASTLayout(int location, int binding, int index, int set, int builtin, bool originUpperLeft)
     : fLocation(location)
     , fBinding(binding)
     , fIndex(index)
     , fSet(set)
     , fBuiltin(builtin)
-    , fOriginUpperLeft(originUpperLeft)
-    , fOverrideCoverage(overrideCoverage)
-    , fBlendSupportAllEquations(blendSupportAllEquations) {}
+    , fOriginUpperLeft(originUpperLeft) {}
 
     std::string description() const {
         std::string result;
@@ -58,14 +55,6 @@ struct ASTLayout : public ASTNode {
             result += separator + "origin_upper_left";
             separator = ", ";
         }
-        if (fOverrideCoverage) {
-            result += separator + "override_coverage";
-            separator = ", ";
-        }
-        if (fBlendSupportAllEquations) {
-            result += separator + "blend_support_all_equations";
-            separator = ", ";
-        }
         if (result.length() > 0) {
             result = "layout (" + result + ")";
         }
@@ -78,8 +67,6 @@ struct ASTLayout : public ASTNode {
     const int fSet;
     const int fBuiltin;
     const bool fOriginUpperLeft;
-    const bool fOverrideCoverage;
-    const bool fBlendSupportAllEquations;
 };
 
 } // namespace
diff --git a/src/sksl/ast/SkSLASTModifiersDeclaration.h b/src/sksl/ast/SkSLASTModifiersDeclaration.h
deleted file mode 100644
index f5cc620899..0000000000
--- a/src/sksl/ast/SkSLASTModifiersDeclaration.h
+++ /dev/null
@@ -1,37 +0,0 @@
-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- 
-#ifndef SKSL_ASTMODIFIERDECLARATION
-#define SKSL_ASTMODIFIERDECLARATION
-
-#include "SkSLASTDeclaration.h"
-#include "SkSLASTModifiers.h"
-
-namespace SkSL {
-
-/**
- * A declaration that consists only of modifiers, e.g.:
- *
- * layout(blend_support_all_equations) out;
- */
-struct ASTModifiersDeclaration : public ASTDeclaration {
-    ASTModifiersDeclaration(ASTModifiers modifiers)
-    : INHERITED(Position(), kModifiers_Kind)
-    , fModifiers(modifiers) {}
-
-    std::string description() const {
-        return fModifiers.description() + ";";
-    }
-
-    ASTModifiers fModifiers;
-
-    typedef ASTDeclaration INHERITED;
-};
-
-} // namespace
-
-#endif
diff --git a/src/sksl/ast/SkSLASTPrecision.h b/src/sksl/ast/SkSLASTPrecision.h
deleted file mode 100644
index a7df57948e..0000000000
--- a/src/sksl/ast/SkSLASTPrecision.h
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * Copyright 2016 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- 
-#ifndef SKSL_ASTPRECISION
-#define SKSL_ASTPRECISION
-
-#include "SkSLASTDeclaration.h"
-#include "../ir/SkSLModifiers.h"
-
-namespace SkSL {
-
-/**
- * Represents a precision declaration (e.g. 'precision mediump float;').
- */
-struct ASTPrecision : public ASTDeclaration {
-    // FIXME handle the type
-    ASTPrecision(Position position, Modifiers::Flag precision)
-    : INHERITED(position, kPrecision_Kind)
-    , fPrecision(precision) {}
-
-    std::string description() const {
-        switch (fPrecision) {
-            case Modifiers::kLowp_Flag: return "precision lowp float;";
-            case Modifiers::kMediump_Flag: return "precision mediump float;";
-            case Modifiers::kHighp_Flag: return "precision highp float;";
-            default: 
-                ASSERT(false); 
-                return "<error>";
-        }
-        ASSERT(false);
-        return "<error>";
-    }
-
-    const Modifiers::Flag fPrecision;
-
-    typedef ASTDeclaration INHERITED;
-};
-
-} // namespace
-
-#endif