cc: More consistent reasoning about display list memory usage.

This refines "picture memory usage" methods to be more consistent.
In particular:

* DisplayItem::external_memory_usage_ replaces picture_memory_usage_, and only
  refers to memory owned by the display item but not allocated within it (since
  that memory can already be accounted for by measuring the ListContainer).

* DisplayItemList separately tracks the memory allocated within items_,
  external memory usage due to those items, and memory usage due to the cached
  SkPicture, when one is used. These are added to produce total memory usage.

BUG=481083
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/1226503006

Cr-Commit-Position: refs/heads/master@{#337911}

1 files changed, 2 insertions, 2 deletions

diff --git a/cc/debug/rasterize_and_record_benchmark.cc b/cc/debug/rasterize_and_record_benchmark.cc
index bed367d..b474e43 100644
--- a/cc/debug/rasterize_and_record_benchmark.cc
+++ b/cc/debug/rasterize_and_record_benchmark.cc
@@ -223,9 +223,9 @@ void RasterizeAndRecordBenchmark::RunOnDisplayListLayer(
 
         if (memory_used) {
           // Verify we are recording the same thing each time.
-          DCHECK(memory_used == display_list->PictureMemoryUsage());
+          DCHECK_EQ(memory_used, display_list->ApproximateMemoryUsage());
         } else {
-          memory_used = display_list->PictureMemoryUsage();
+          memory_used = display_list->ApproximateMemoryUsage();
         }
 
         timer.NextLap();