Remove cullRect() from PaintOpBuffer.

cc/paint/paint_op_buffer.cc

Index: cc/paint/paint_op_buffer.cc
diff --git a/cc/paint/paint_op_buffer.cc b/cc/paint/paint_op_buffer.cc
index d6556ab50df49e5de58a7f60b50fb2cd6141b668..e7d825958426945c4d708811930ac9a633c4bbb2 100644
--- a/cc/paint/paint_op_buffer.cc
+++ b/cc/paint/paint_op_buffer.cc
@@ -582,9 +582,7 @@ DrawTextBlobOp::DrawTextBlobOp(sk_sp<SkTextBlob> blob,
 
 DrawTextBlobOp::~DrawTextBlobOp() = default;
 
-PaintOpBuffer::PaintOpBuffer() : cull_rect_(SkRect::MakeEmpty()) {}
-
-PaintOpBuffer::PaintOpBuffer(const SkRect& cull_rect) : cull_rect_(cull_rect) {}
+PaintOpBuffer::PaintOpBuffer() = default;
 
 PaintOpBuffer::~PaintOpBuffer() {
   Reset();