Rename @index -> @blend_src

Bug: dawn:2380
Change-Id: I08b73f95d7ff8f196ceac46a16a7f73e7abdf998
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/171841
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/tint/lang/wgsl/ast/BUILD.cmake b/src/tint/lang/wgsl/ast/BUILD.cmake
index 767496f..fd20e97 100644
--- a/src/tint/lang/wgsl/ast/BUILD.cmake
+++ b/src/tint/lang/wgsl/ast/BUILD.cmake
@@ -55,6 +55,8 @@
   lang/wgsl/ast/binding_attribute.h
   lang/wgsl/ast/bitcast_expression.cc
   lang/wgsl/ast/bitcast_expression.h
+  lang/wgsl/ast/blend_src_attribute.cc
+  lang/wgsl/ast/blend_src_attribute.h
   lang/wgsl/ast/block_statement.cc
   lang/wgsl/ast/block_statement.h
   lang/wgsl/ast/bool_literal_expression.cc
@@ -125,8 +127,6 @@
   lang/wgsl/ast/increment_decrement_statement.h
   lang/wgsl/ast/index_accessor_expression.cc
   lang/wgsl/ast/index_accessor_expression.h
-  lang/wgsl/ast/index_attribute.cc
-  lang/wgsl/ast/index_attribute.h
   lang/wgsl/ast/int_literal_expression.cc
   lang/wgsl/ast/int_literal_expression.h
   lang/wgsl/ast/internal_attribute.cc
@@ -235,6 +235,7 @@
   lang/wgsl/ast/binary_expression_test.cc
   lang/wgsl/ast/binding_attribute_test.cc
   lang/wgsl/ast/bitcast_expression_test.cc
+  lang/wgsl/ast/blend_src_attribute_test.cc
   lang/wgsl/ast/block_statement_test.cc
   lang/wgsl/ast/bool_literal_expression_test.cc
   lang/wgsl/ast/break_if_statement_test.cc
@@ -269,7 +270,6 @@
   lang/wgsl/ast/if_statement_test.cc
   lang/wgsl/ast/increment_decrement_statement_test.cc
   lang/wgsl/ast/index_accessor_expression_test.cc
-  lang/wgsl/ast/index_attribute_test.cc
   lang/wgsl/ast/int_literal_expression_test.cc
   lang/wgsl/ast/interpolate_attribute_test.cc
   lang/wgsl/ast/location_attribute_test.cc