Add support for input attachments in SkSL spirv

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=5115

Change-Id: I3e03a465a10c9aff62491d0f6e71105d1b650dab
Reviewed-on: https://skia-review.googlesource.com/5115
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
diff --git a/src/sksl/ir/SkSLConstructor.h b/src/sksl/ir/SkSLConstructor.h
index 92f7580..63c692b 100644
--- a/src/sksl/ir/SkSLConstructor.h
+++ b/src/sksl/ir/SkSLConstructor.h
@@ -4,7 +4,7 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
- 
+
 #ifndef SKSL_CONSTRUCTOR
 #define SKSL_CONSTRUCTOR
 
@@ -16,7 +16,7 @@
  * Represents the construction of a compound type, such as "vec2(x, y)".
  */
 struct Constructor : public Expression {
-    Constructor(Position position, const Type& type, 
+    Constructor(Position position, const Type& type,
                 std::vector<std::unique_ptr<Expression>> arguments)
     : INHERITED(position, kConstructor_Kind, type)
     , fArguments(std::move(arguments)) {}