Switch GrMeshDrawOp::Target to be the stand alone GrMeshDrawTarget class

The Tessellator classes will survive in the NGA and they use
GrMeshDrawOp::Target - but GrMeshDrawOp will not survive.

This is a prelude to making all the remaining GrOp-derived classes OGA-only.

Bug: skia:11837
Change-Id: I62dc92e5f42d672342113f12dcedf3435fab993f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/419198
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
diff --git a/src/gpu/ops/GrOvalOpFactory.cpp b/src/gpu/ops/GrOvalOpFactory.cpp
index 843b54d..8d29f16 100644
--- a/src/gpu/ops/GrOvalOpFactory.cpp
+++ b/src/gpu/ops/GrOvalOpFactory.cpp
@@ -1293,7 +1293,7 @@
                                                  renderPassXferBarriers, colorLoadOp);
     }
 
-    void onPrepareDraws(Target* target) override {
+    void onPrepareDraws(GrMeshDrawTarget* target) override {
         if (!fProgramInfo) {
             this->createProgramInfo(target);
             if (!fProgramInfo) {
@@ -1655,7 +1655,7 @@
                                                  renderPassXferBarriers, colorLoadOp);
     }
 
-    void onPrepareDraws(Target* target) override {
+    void onPrepareDraws(GrMeshDrawTarget* target) override {
         if (!fProgramInfo) {
             this->createProgramInfo(target);
             if (!fProgramInfo) {
@@ -1986,7 +1986,7 @@
                                                  renderPassXferBarriers, colorLoadOp);
     }
 
-    void onPrepareDraws(Target* target) override {
+    void onPrepareDraws(GrMeshDrawTarget* target) override {
         if (!fProgramInfo) {
             this->createProgramInfo(target);
             if (!fProgramInfo) {
@@ -2258,7 +2258,7 @@
                                                  renderPassXferBarriers, colorLoadOp);
     }
 
-    void onPrepareDraws(Target* target) override {
+    void onPrepareDraws(GrMeshDrawTarget* target) override {
         if (!fProgramInfo) {
             this->createProgramInfo(target);
         }
@@ -2662,7 +2662,7 @@
                                                  renderPassXferBarriers, colorLoadOp);
     }
 
-    void onPrepareDraws(Target* target) override {
+    void onPrepareDraws(GrMeshDrawTarget* target) override {
         if (!fProgramInfo) {
             this->createProgramInfo(target);
             if (!fProgramInfo) {
@@ -2983,7 +2983,7 @@
                                                  renderPassXferBarriers, colorLoadOp);
     }
 
-    void onPrepareDraws(Target* target) override {
+    void onPrepareDraws(GrMeshDrawTarget* target) override {
         if (!fProgramInfo) {
             this->createProgramInfo(target);
             if (!fProgramInfo) {