Raster display item lists via a visual rect RTree.

cc/playback/display_item_list.h

 // Copyright 2014 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.
 
 #ifndef CC_PLAYBACK_DISPLAY_ITEM_LIST_H_
 #define CC_PLAYBACK_DISPLAY_ITEM_LIST_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <utility>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/contiguous_container.h"
+#include "cc/base/rtree.h"
 #include "cc/playback/discardable_image_map.h"
 #include "cc/playback/display_item.h"
 #include "cc/playback/display_item_list_settings.h"
 #include "third_party/skia/include/core/SkPicture.h"
 #include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/rect_conversions.h"
 
 class SkCanvas;
 class SkPictureRecorder;
 
 namespace cc {
 class DisplayItem;
 class DrawingDisplayItem;
 class ImageSerializationProcessor;
 
 namespace proto {
 class DisplayItemList;
 }
 
 class CC_EXPORT DisplayItemList
     : public base::RefCountedThreadSafe<DisplayItemList> {
  public:
-  // Creates a display item list. If picture caching is used, then layer_rect
-  // specifies the cull rect of the display item list (the picture will not
-  // exceed this rect). If picture caching is not used, then the given rect can
-  // be empty.
-  // TODO(vmpstr): Maybe this cull rect can be part of the settings instead.
+  // Creates a display item list.
   static scoped_refptr<DisplayItemList> Create(
-      const gfx::Rect& layer_rect,
       const DisplayItemListSettings& settings);
 
   // Creates a DisplayItemList from a Protobuf.
   // TODO(dtrainor): Pass in a list of possible DisplayItems to reuse
   // (crbug.com/548434).
   static scoped_refptr<DisplayItemList> CreateFromProto(
       const proto::DisplayItemList& proto,
       ImageSerializationProcessor* image_serialization_processor);
 
   // Creates a Protobuf representing the state of this DisplayItemList.
   // TODO(dtrainor): Don't resend DisplayItems that were already serialized
   // (crbug.com/548434).
   void ToProtobuf(proto::DisplayItemList* proto,
                   ImageSerializationProcessor* image_serialization_processor);
 
   void Raster(SkCanvas* canvas,
               SkPicture::AbortCallback* callback,
               const gfx::Rect& canvas_target_playback_rect,
               float contents_scale) const;
 
-  // This is a fast path for use only if canvas_ is set and
-  // retain_individual_display_items_ is false. This method also updates
-  // approximate_op_count_.
-  void RasterIntoCanvas(const DisplayItem& display_item);
-
   // Because processing happens in this function, all the set up for
   // this item should be done via the args, which is why the return
   // type needs to be const, to prevent set-after-processing mistakes.
   template <typename DisplayItemType, typename... Args>
   const DisplayItemType& CreateAndAppendItem(const gfx::Rect& visual_rect,
                                              Args&&... args) {
     visual_rects_.push_back(visual_rect);
     auto* item = &items_.AllocateAndConstruct<DisplayItemType>(
         std::forward<Args>(args)...);
     approximate_op_count_ += item->ApproximateOpCount();
-    ProcessAppendedItem(item);
     return *item;
   }
 
   // Called after all items are appended, to process the items and, if
   // applicable, create an internally cached SkPicture.
   void Finalize();
 
   void SetIsSuitableForGpuRasterization(bool is_suitable) {
-    is_suitable_for_gpu_rasterization_ = is_suitable;
+    all_items_are_suitable_for_gpu_rasterization_ = is_suitable;
   }
   bool IsSuitableForGpuRasterization() const;
   int ApproximateOpCount() const;
   size_t ApproximateMemoryUsage() const;
   bool ShouldBeAnalyzedForSolidColor() const;
 
-  bool RetainsIndividualDisplayItems() const;
-
   std::unique_ptr<base::trace_event::ConvertableToTraceFormat> AsValue(
       bool include_items) const;
 
   void EmitTraceSnapshot() const;
 
   void GenerateDiscardableImagesMetadata();
   void GetDiscardableImagesInRect(const gfx::Rect& rect,
                                   float raster_scale,
                                   std::vector<DrawImage>* images);
 
   gfx::Rect VisualRectForTesting(int index) { return visual_rects_[index]; }
+  void SetRetainVisualRectsForTesting(bool retain) {
+    retain_visual_rects_ = retain;
+  }
 
  private:
-  DisplayItemList(gfx::Rect layer_rect,
-                  const DisplayItemListSettings& display_list_settings,
-                  bool retain_individual_display_items);
+  explicit DisplayItemList(
+      const DisplayItemListSettings& display_list_settings);
   ~DisplayItemList();
 
   void ProcessAppendedItem(const DisplayItem* item);
 
+  gfx::Rect GetQueryRect(const gfx::Rect& rect, float scale) const;
+
+  RTree rtree_;
   ContiguousContainer<DisplayItem> items_;
   // The visual rects associated with each of the display items in the
   // display item list. There is one rect per display item, and the
   // position in |visual_rects_| matches the position of the item in
   // |items_| . These rects are intentionally kept separate
   // because they are not needed while walking the |items_| for raster.
   std::vector<gfx::Rect> visual_rects_;
-  sk_sp<SkPicture> picture_;
+  bool retain_visual_rects_;

[vmpstr, 2016/06/22 20:14:07]

Where are we using this?

[wkorman, 2016/06/24 19:57:14]

In display_item_list_unittest, two main cases:

1. tests that use ValidateDisplayItemListSerialization() end up calling
cc::DisplayItemList::ToProtobuf() after Finalize() is called. Finalize() by
default clears out the visual rects, and ToProtobuf() has:

  DCHECK(items_.size() == visual_rects_.size())
      << "items.size() " << items_.size() << " visual_rects.size() "
      << visual_rects_.size();

which will fail unless we keep the visual rects around. It's a DCHECK so I
figure it is ok in release builds where Blimp will likely be calling
ToProtobuf() after Finalize() but if I'm off base let's discuss further.

2. There are a couple of unit tests for AsValue() which of course need the
visual rects to be around to make sure that part is working as intended.

[vmpstr, 2016/06/24 20:15:33]

Can you put a comment to make it clear that this is for tests?

[wkorman, 2016/06/24 22:39:32]

Done.

 
-  std::unique_ptr<SkPictureRecorder> recorder_;
   const DisplayItemListSettings settings_;
-  bool retain_individual_display_items_;
-
-  gfx::Rect layer_rect_;
-  bool is_suitable_for_gpu_rasterization_;
+  bool all_items_are_suitable_for_gpu_rasterization_;
   int approximate_op_count_;
 
-  // Memory usage due to the cached SkPicture.
-  size_t picture_memory_usage_;
-
   DiscardableImageMap image_map_;
 
   friend class base::RefCountedThreadSafe<DisplayItemList>;
   FRIEND_TEST_ALL_PREFIXES(DisplayItemListTest, ApproximateMemoryUsage);
   DISALLOW_COPY_AND_ASSIGN(DisplayItemList);
 };
 
 }  // namespace cc
 
 #endif  // CC_PLAYBACK_DISPLAY_ITEM_LIST_H_