cc: Don't perform image analysis if the DisplayItemList has no images.

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 fa62a418e9fce2bb5fee71e9f6eb057567ac9171..0a1897852f3e51ca3d91b67460b2d6e84dace61a 100644
--- a/cc/paint/paint_op_buffer.cc
+++ b/cc/paint/paint_op_buffer.cc
@@ -416,6 +416,10 @@ size_t DrawDisplayItemListOp::AdditionalBytesUsed() const {
   return list->ApproximateMemoryUsage();
 }
 
+bool DrawDisplayItemListOp::HasDiscardableImages() const {
+  return list->has_discardable_images();
+}
+
 DrawDisplayItemListOp::DrawDisplayItemListOp(const DrawDisplayItemListOp& op) =
     default;
 
@@ -433,6 +437,12 @@ DrawImageOp::DrawImageOp(const PaintImage& image,
       top(top),
       flags(flags ? *flags : PaintFlags()) {}
 
+bool DrawImageOp::HasDiscardableImages() const {
+  // TODO(khushalsagar): Callers should not be able to change the lazy generated
+  // state for a PaintImage.
+  return image.sk_image()->isLazyGenerated();
+}
+
 DrawImageOp::~DrawImageOp() = default;
 
 DrawImageRectOp::DrawImageRectOp(const PaintImage& image,
@@ -446,6 +456,10 @@ DrawImageRectOp::DrawImageRectOp(const PaintImage& image,
       dst(dst),
       constraint(constraint) {}
 
+bool DrawImageRectOp::HasDiscardableImages() const {
+  return image.sk_image()->isLazyGenerated();
+}
+
 DrawImageRectOp::~DrawImageRectOp() = default;
 
 DrawPosTextOp::DrawPosTextOp(size_t bytes,
@@ -464,6 +478,10 @@ size_t DrawRecordOp::AdditionalBytesUsed() const {
   return record->approximateBytesUsed();
 }
 
+bool DrawRecordOp::HasDiscardableImages() const {
+  return record->HasDiscardableImages();
+}
+
 DrawTextBlobOp::DrawTextBlobOp(sk_sp<SkTextBlob> blob,
                                SkScalar x,
                                SkScalar y,