Remove dead code for 3x3 matrices (#23363)

Co-authored-by: Mike Reed <reed@google.com>
diff --git a/shell/common/canvas_spy.cc b/shell/common/canvas_spy.cc
index 0b884a0..c714666 100644
--- a/shell/common/canvas_spy.cc
+++ b/shell/common/canvas_spy.cc
@@ -51,11 +51,6 @@
 
 void DidDrawCanvas::willRestore() {}
 
-#ifdef SK_SUPPORT_LEGACY_CANVASMATRIX33
-void DidDrawCanvas::didConcat(const SkMatrix& matrix) {}
-void DidDrawCanvas::didSetMatrix(const SkMatrix& matrix) {}
-#endif
-
 void DidDrawCanvas::didConcat44(const SkM44&) {}
 
 void DidDrawCanvas::didScale(SkScalar, SkScalar) {}
diff --git a/shell/common/canvas_spy.h b/shell/common/canvas_spy.h
index aed5c20..eb868e0 100644
--- a/shell/common/canvas_spy.h
+++ b/shell/common/canvas_spy.h
@@ -70,10 +70,6 @@
   void willRestore() override;
 
   // |SkCanvasVirtualEnforcer<SkNoDrawCanvas>|
-#ifdef SK_SUPPORT_LEGACY_CANVASMATRIX33
-  void didConcat(const SkMatrix&) override;
-  void didSetMatrix(const SkMatrix&) override;
-#endif
   void didConcat44(const SkM44&) override;
   void didScale(SkScalar, SkScalar) override;
   void didTranslate(SkScalar, SkScalar) override;
diff --git a/testing/mock_canvas.cc b/testing/mock_canvas.cc
index 42f8216..7d0fab5 100644
--- a/testing/mock_canvas.cc
+++ b/testing/mock_canvas.cc
@@ -56,15 +56,6 @@
   current_layer_--;  // Must go here; func params order of eval is undefined
 }
 
-#ifdef SK_SUPPORT_LEGACY_CANVASMATRIX33
-void MockCanvas::didConcat(const SkMatrix& matrix) {
-  this->didConcat44(SkM44(matrix));
-}
-void MockCanvas::didSetMatrix(const SkMatrix& matrix) {
-  this->didSetM44(SkM44(matrix));
-}
-#endif
-
 void MockCanvas::didConcat44(const SkM44& matrix) {
   draw_calls_.emplace_back(DrawCall{current_layer_, ConcatMatrixData{matrix}});
 }
diff --git a/testing/mock_canvas.h b/testing/mock_canvas.h
index f073246..62b9b9e 100644
--- a/testing/mock_canvas.h
+++ b/testing/mock_canvas.h
@@ -144,10 +144,6 @@
   SaveLayerStrategy getSaveLayerStrategy(const SaveLayerRec& rec) override;
   void willRestore() override;
   void didRestore() override {}
-#ifdef SK_SUPPORT_LEGACY_CANVASMATRIX33
-  void didConcat(const SkMatrix& matrix) override;
-  void didSetMatrix(const SkMatrix& matrix) override;
-#endif
   void didConcat44(const SkM44&) override;
   void didSetM44(const SkM44&) override;
   void didScale(SkScalar x, SkScalar y) override;