Add a kWireframe flag to GrPipeline

Adds the flag to GrPipeline, as well as a 'w' keystroke in viewer for
toggling the alternate global wireframe mode.

Change-Id: I385c31320a5fa2cec79b527a91fa876b19cdff89
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/260747
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/GrOpsRenderPass.cpp b/src/gpu/GrOpsRenderPass.cpp
index 85ae57d..c506110 100644
--- a/src/gpu/GrOpsRenderPass.cpp
+++ b/src/gpu/GrOpsRenderPass.cpp
@@ -46,6 +46,8 @@
              this->gpu()->caps()->instanceAttribSupport());
     SkASSERT(!programInfo.pipeline().usesConservativeRaster() ||
              this->gpu()->caps()->conservativeRasterSupport());
+    SkASSERT(!programInfo.pipeline().isWireframe() ||
+             this->gpu()->caps()->wireframeSupport());
 
     programInfo.compatibleWithMeshes(meshes, meshCount);
     programInfo.checkAllInstantiated();