Add Make factory functions to literal types.

This is mostly for consistency with other IRNode types; there isn't any
optimization opportunity or error checking for literals.

Change-Id: I0e6a55cddbd814585ecafeddab4e591fe5113911
Bug: skia:11342
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/383996
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
diff --git a/src/sksl/SkSLRehydrator.cpp b/src/sksl/SkSLRehydrator.cpp
index 9f15deb..ce02ed3 100644
--- a/src/sksl/SkSLRehydrator.cpp
+++ b/src/sksl/SkSLRehydrator.cpp
@@ -288,7 +288,7 @@
                 int value = this->readS32();
                 // enum variables aren't really 'declared', but we have to create a declaration to
                 // store the value
-                auto valueLiteral = std::make_unique<IntLiteral>(fContext, /*offset=*/-1, value);
+                auto valueLiteral = IntLiteral::Make(fContext, /*offset=*/-1, value);
                 auto declaration = std::make_unique<VarDeclaration>(&v, &v.type(), /*arraySize=*/0,
                                                                     std::move(valueLiteral));
                 v.setDeclaration(declaration.get());
@@ -446,7 +446,7 @@
         }
         case Rehydrator::kBoolLiteral_Command: {
             bool value = this->readU8();
-            return std::make_unique<BoolLiteral>(fContext, -1, value);
+            return BoolLiteral::Make(fContext, /*offset=*/-1, value);
         }
         case Rehydrator::kConstructor_Command: {
             const Type* type = this->type();
@@ -470,7 +470,7 @@
             const Type* type = this->type();
             FloatIntUnion u;
             u.fInt = this->readS32();
-            return std::make_unique<FloatLiteral>(-1, u.fFloat, type);
+            return FloatLiteral::Make(/*offset=*/-1, u.fFloat, type);
         }
         case Rehydrator::kFunctionCall_Command: {
             const Type* type = this->type();
@@ -492,7 +492,7 @@
         case Rehydrator::kIntLiteral_Command: {
             const Type* type = this->type();
             int value = this->readS32();
-            return std::make_unique<IntLiteral>(-1, value, type);
+            return IntLiteral::Make(/*offset=*/-1, value, type);
         }
         case Rehydrator::kPostfix_Command: {
             Token::Kind op = (Token::Kind) this->readU8();