cc: More consistent reasoning about display list memory usage.

cc/playback/display_item_list_unittest.cc

Index: cc/playback/display_item_list_unittest.cc
diff --git a/cc/playback/display_item_list_unittest.cc b/cc/playback/display_item_list_unittest.cc
index a7bb96faabd7f8ee7d9f91a5555e2bf5939d1a4e..dd6fb5cd8e4b079e1f450b9e2bfab55a68056796 100644
--- a/cc/playback/display_item_list_unittest.cc
+++ b/cc/playback/display_item_list_unittest.cc
@@ -284,7 +284,7 @@ TEST(DisplayItemListTest, CompactingItems) {
   EXPECT_EQ(0, memcmp(pixels, expected_pixels, 4 * 100 * 100));
 }
 
-TEST(DisplayItemListTest, PictureMemoryUsage) {
+TEST(DisplayItemListTest, ApproximateMemoryUsage) {
   scoped_refptr<DisplayItemList> list;
   size_t memory_usage;
 
@@ -307,7 +307,7 @@ TEST(DisplayItemListTest, PictureMemoryUsage) {
   auto* item = list->CreateAndAppendItem<DrawingDisplayItem>();
   item->SetNew(picture);
   list->Finalize();
-  memory_usage = list->PictureMemoryUsage();
+  memory_usage = list->ApproximateMemoryUsage();
   EXPECT_GE(memory_usage, picture_size);
   EXPECT_LE(memory_usage, 2 * picture_size);
 
@@ -316,7 +316,7 @@ TEST(DisplayItemListTest, PictureMemoryUsage) {
   item = list->CreateAndAppendItem<DrawingDisplayItem>();
   item->SetNew(picture);
   list->Finalize();
-  memory_usage = list->PictureMemoryUsage();
+  memory_usage = list->ApproximateMemoryUsage();
   EXPECT_GE(memory_usage, picture_size);
   EXPECT_LE(memory_usage, 2 * picture_size);
 
@@ -329,7 +329,7 @@ TEST(DisplayItemListTest, PictureMemoryUsage) {
   item = list->CreateAndAppendItem<DrawingDisplayItem>();
   item->SetNew(picture);
   list->Finalize();
-  memory_usage = list->PictureMemoryUsage();
+  memory_usage = list->ApproximateMemoryUsage();
   EXPECT_EQ(static_cast<size_t>(0), memory_usage);
 }