Notify paint for each frame

third_party/WebKit/Source/platform/graphics/paint/PaintController.cpp

 // 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 "platform/graphics/paint/PaintController.h"
 
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/graphics/paint/DrawingDisplayItem.h"
 #include "platform/instrumentation/tracing/TraceEvent.h"
 #include "platform/wtf/AutoReset.h"
@@ skipping 267 matching lines @@
         new_display_item_list_[index].AsDebugString().Utf8().data(), index);
 #endif
     NOTREACHED();
   }
   AddItemToIndexIfNeeded(display_item, new_display_item_list_.size() - 1,
                          new_display_item_indices_by_client_);
 #endif  // DCHECK_IS_ON()
 
   if (RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled())
     CheckUnderInvalidation();
+
+  if (!frame_first_paints_.back().first_painted && display_item.IsDrawing() &&

[Xianzhu, 2017/05/09 21:07:56]

PaintController might paint something before BeginFrame() (e.g. when
PaintController is used to paint an SVGImage), and back() will crash in the
case.

I think we can call BeginFrame(nullptr) from PaintController::PaintController()
to avoid the problem. (This will also enable us to combine the first paint data
in this PaintController into another PaintController on which we replay the
recorded result of this PaintController, in the future). 

[Zhen Wang, 2017/05/09 22:59:40]

Done.

+      // Here we ignore all document-background paintings because we don't
+      // know if the background is default. ViewPainter should have called
+      // setFirstPainted() if this display item is for non-default
+      // background.
+      display_item.GetType() != DisplayItem::kDocumentBackground &&
+      display_item.DrawsContent()) {
+    SetFirstPainted();
+  }
 }
 
 DisplayItem& PaintController::MoveItemFromCurrentListToNewList(size_t index) {
   items_moved_into_new_list_.resize(
       current_paint_artifact_.GetDisplayItemList().size());
   items_moved_into_new_list_[index] = new_display_item_list_.size();
   return new_display_item_list_.AppendByMoving(
       current_paint_artifact_.GetDisplayItemList()[index]);
 }
 
@@ skipping 272 matching lines @@
     if (item.IsCacheable()) {
       item.Client().SetDisplayItemsCached(current_cache_generation_);
     } else {
       if (item.Client().IsJustCreated())
         item.Client().ClearIsJustCreated();
       if (item.SkippedCache())
         skipped_cache_clients.push_back(&item.Client());
     }
   }
 
-  if (!first_painted_) {
-    for (const auto& item : new_display_item_list_) {
-      if (item.IsDrawing() &&
-          // Here we ignore all document-background paintings because we don't
-          // know if the background is default. ViewPainter should have called
-          // setFirstPainted() if this display item is for non-default
-          // background.
-          item.GetType() != DisplayItem::kDocumentBackground &&
-          item.DrawsContent()) {
-        first_painted_ = true;
-        break;
-      }
-    }
-  }
-
   for (auto* client : skipped_cache_clients)
     client->SetDisplayItemsUncached();
 
   // The new list will not be appended to again so we can release unused memory.
   new_display_item_list_.ShrinkToFit();
   current_paint_artifact_ = PaintArtifact(
       std::move(new_display_item_list_), new_paint_chunks_.ReleasePaintChunks(),
       num_slow_paths <= kMaxNumberOfSlowPathsBeforeVeto);
   ResetCurrentListIndices();
   out_of_order_item_indices_.clear();
@@ skipping 332 matching lines @@
               0, new_display_item_list_.size(),
               show_paint_records
                   ? (DisplayItemList::JsonOptions::kShowPaintRecords |
                      DisplayItemList::JsonOptions::kShowClientDebugName)
                   : DisplayItemList::JsonOptions::kShowClientDebugName)
           ->ToPrettyJSONString()
           .Utf8()
           .data());
 }
 
+void PaintController::SetFirstPainted() {
+  frame_first_paints_.back().first_painted = true;
+}
+
+void PaintController::SetTextPainted() {
+  frame_first_paints_.back().text_painted = true;
+}
+
+void PaintController::SetImagePainted() {
+  frame_first_paints_.back().image_painted = true;
+}
+
+void PaintController::BeginFrame(const void* frame) {
+  frame_first_paints_.push_back(FrameFirstPaint(frame));
+}
+
+FrameFirstPaint PaintController::EndFrame(const void* frame) {
+  FrameFirstPaint result = frame_first_paints_.back();
+  DCHECK(result.frame == frame);
+  frame_first_paints_.pop_back();
+  return result;
+}
+
 }  // namespace blink