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

cc/paint/paint_op_buffer.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/paint/paint_op_buffer.h"
 
 #include "cc/paint/display_item_list.h"
 #include "cc/paint/paint_record.h"
 #include "third_party/skia/include/core/SkAnnotation.h"
 
@@ skipping 467 matching lines @@
 AnnotateOp::~AnnotateOp() = default;
 
 DrawDisplayItemListOp::DrawDisplayItemListOp(
     scoped_refptr<DisplayItemList> list)
     : list(list) {}
 
 size_t DrawDisplayItemListOp::AdditionalBytesUsed() const {
   return list->ApproximateMemoryUsage();
 }
 
+bool DrawDisplayItemListOp::HasDiscardableImages() const {
+  return list->has_discardable_images();
+}
+
 DrawDisplayItemListOp::DrawDisplayItemListOp(const DrawDisplayItemListOp& op) =
     default;
 
 DrawDisplayItemListOp& DrawDisplayItemListOp::operator=(
     const DrawDisplayItemListOp& op) = default;
 
 DrawDisplayItemListOp::~DrawDisplayItemListOp() = default;
 
 DrawImageOp::DrawImageOp(const PaintImage& image,
                          SkScalar left,
                          SkScalar top,
                          const PaintFlags* flags)
     : PaintOpWithFlags(flags ? *flags : PaintFlags()),
       image(image),
       left(left),
       top(top) {}
 
+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,
                                  const SkRect& src,
                                  const SkRect& dst,
                                  const PaintFlags* flags,
                                  PaintCanvas::SrcRectConstraint constraint)
     : PaintOpWithFlags(flags ? *flags : PaintFlags()),
       image(image),
       src(src),
       dst(dst),
       constraint(constraint) {}
 
+bool DrawImageRectOp::HasDiscardableImages() const {
+  return image.sk_image()->isLazyGenerated();
+}
+
 DrawImageRectOp::~DrawImageRectOp() = default;
 
 DrawPosTextOp::DrawPosTextOp(size_t bytes,
                              size_t count,
                              const PaintFlags& flags)
     : PaintOpWithArray(flags, bytes, count) {}
 
 DrawPosTextOp::~DrawPosTextOp() = default;
 
 DrawRecordOp::DrawRecordOp(sk_sp<const PaintRecord> record)
     : record(std::move(record)) {}
 
 DrawRecordOp::~DrawRecordOp() = default;
 
 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,
                                const PaintFlags& flags)
     : PaintOpWithFlags(flags), blob(std::move(blob)), x(x), y(y) {}
 
 DrawTextBlobOp::~DrawTextBlobOp() = default;
 
 PaintOpBuffer::PaintOpBuffer() : cull_rect_(SkRect::MakeEmpty()) {}
 
@@ skipping 126 matching lines @@
   return std::make_pair(op, skip);
 }
 
 void PaintOpBuffer::ShrinkToFit() {
   if (!used_ || used_ == reserved_)
     return;
   ReallocBuffer(used_);
 }
 
 }  // namespace cc