Make SkM44 public

Need to migrate clients from private/ to core/ include
Unexperimentalize concat44() methods on SkCanvas

Change-Id: I64b8816722a9d93316cb8b8691d2d9a3e36f167f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/272464
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Reed <reed@google.com>
diff --git a/samplecode/SampleClip.cpp b/samplecode/SampleClip.cpp
index 90f2c7f..4f4ff25 100644
--- a/samplecode/SampleClip.cpp
+++ b/samplecode/SampleClip.cpp
@@ -527,7 +527,7 @@
 
         if (fShowUnclipped) {
             canvas->save();
-            canvas->experimental_concat44(mx);
+            canvas->concat44(mx);
             paint.setAlphaf(0.33f);
             canvas->drawPath(fPath, paint);
             paint.setAlphaf(1.f);
@@ -542,7 +542,7 @@
             planeColor = SK_ColorRED;
         }
         canvas->save();
-        canvas->experimental_concat44(mx);
+        canvas->concat44(mx);
         canvas->drawPath(*path, paint);
         canvas->restore();
 
@@ -585,7 +585,7 @@
         SkPaint paint;
 
         canvas->save();
-        canvas->experimental_concat44(this->get44({0, 0, 300, 300}));
+        canvas->concat44(this->get44({0, 0, 300, 300}));
 
         const SkPoint* tex = nullptr;
         const SkColor* col = nullptr;