cc: Update discardable image metadata generation to get PaintImages.

cc/paint/display_item_list.cc

 // 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.
 
 #include "cc/paint/display_item_list.h"
 
 #include <stddef.h>
 
 #include <string>
 
 #include "base/memory/ptr_util.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/strings/stringprintf.h"
 #include "base/trace_event/trace_event.h"
 #include "base/trace_event/trace_event_argument.h"
 #include "cc/base/math_util.h"
 #include "cc/base/render_surface_filters.h"
 #include "cc/debug/picture_debug_util.h"
 #include "cc/paint/clip_display_item.h"
 #include "cc/paint/clip_path_display_item.h"
 #include "cc/paint/compositing_display_item.h"
+#include "cc/paint/discardable_image_store.h"
 #include "cc/paint/drawing_display_item.h"
 #include "cc/paint/filter_display_item.h"
 #include "cc/paint/float_clip_display_item.h"
 #include "cc/paint/largest_display_item.h"
 #include "cc/paint/transform_display_item.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
 #include "third_party/skia/include/core/SkPaint.h"
 #include "third_party/skia/include/core/SkPictureRecorder.h"
 #include "ui/gfx/geometry/rect.h"
@@ skipping 495 matching lines @@
 
 void DisplayItemList::GenerateDiscardableImagesMetadata() {
   // This should be only called once.
   DCHECK(image_map_.empty());
   if (!has_discardable_images_)
     return;
 
   gfx::Rect bounds = rtree_.GetBounds();
   DiscardableImageMap::ScopedMetadataGenerator generator(
       &image_map_, gfx::Size(bounds.right(), bounds.bottom()));
-  auto* canvas = generator.canvas();
-  for (const auto& item : items_)
-    RasterItem(item, canvas, nullptr);
+  GatherDiscardableImages(generator.image_store());
+}
+
+void DisplayItemList::GatherDiscardableImages(
+    DiscardableImageStore* image_store) const {
+  // TODO(khushalsagar): Could we avoid this if the data was already stored in
+  // the |image_map_|?
+  SkCanvas* canvas = image_store->NoDrawCanvas();
+  for (const auto& item : items_) {
+    if (item.type == DisplayItem::DRAWING) {
+      const auto& drawing_item = static_cast<const DrawingDisplayItem&>(item);
+      drawing_item.picture->GatherDiscardableImages(image_store);
+    } else {
+      RasterItem(item, canvas, nullptr);
+    }
+  }
 }
 
 void DisplayItemList::GetDiscardableImagesInRect(
     const gfx::Rect& rect,
     float contents_scale,
     const gfx::ColorSpace& target_color_space,
     std::vector<DrawImage>* images) {
   image_map_.GetDiscardableImagesInRect(rect, contents_scale,
                                         target_color_space, images);
 }
 
 gfx::Rect DisplayItemList::GetRectForImage(ImageId image_id) const {
   return image_map_.GetRectForImage(image_id);
 }
 
 }  // namespace cc