Forward EXT_blend_func_extended entry points in the passthrough decoder.

BUG=angleproject:3401

Change-Id: If16d04ab38673af68b582804f2ca9cf168e23231
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1584371Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#654632}

gpu/command_buffer/service/gles2_cmd_decoder_passthrough_doers.cc

@@ -4872,7 +4872,8 @@ error::Error GLES2DecoderPassthroughImpl::DoBindFragDataLocationIndexedEXT(
     GLuint colorNumber,
     GLuint index,
     const char* name) {
-  NOTIMPLEMENTED();
+  api()->glBindFragDataLocationIndexedFn(
+      GetProgramServiceID(program, resources_), colorNumber, index, name);
   return error::kNoError;
 }
 
@@ -4880,7 +4881,8 @@ error::Error GLES2DecoderPassthroughImpl::DoBindFragDataLocationEXT(
     GLuint program,
     GLuint colorNumber,
     const char* name) {
-  NOTIMPLEMENTED();
+  api()->glBindFragDataLocationFn(GetProgramServiceID(program, resources_),
+                                  colorNumber, name);
   return error::kNoError;
 }
 
@@ -4888,7 +4890,8 @@ error::Error GLES2DecoderPassthroughImpl::DoGetFragDataIndexEXT(
     GLuint program,
     const char* name,
     GLint* index) {
-  NOTIMPLEMENTED();
+  *index = api()->glGetFragDataIndexFn(GetProgramServiceID(program, resources_),
+                                       name);
   return error::kNoError;
 }