Notify paint for each frame

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

Index: third_party/WebKit/Source/platform/graphics/paint/PaintController.h
diff --git a/third_party/WebKit/Source/platform/graphics/paint/PaintController.h b/third_party/WebKit/Source/platform/graphics/paint/PaintController.h
index 5bfc86ec8e4156d37fca6adf2b74337b78eb6f6e..b38474388930fb85fc2f5d767347bba8c90d1502 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/PaintController.h
+++ b/third_party/WebKit/Source/platform/graphics/paint/PaintController.h
@@ -161,12 +161,12 @@ class PLATFORM_EXPORT PaintController {
     subsequence_caching_disabled_ = disable;
   }
 
-  bool FirstPainted() const { return first_painted_; }
-  void SetFirstPainted() { first_painted_ = true; }
-  bool TextPainted() const { return text_painted_; }
-  void SetTextPainted() { text_painted_ = true; }
-  bool ImagePainted() const { return image_painted_; }
-  void SetImagePainted() { image_painted_ = true; }
+  bool FirstPainted(const void* frame) const;
+  void SetFirstPainted();
+  bool TextPainted(const void* frame) const;
+  void SetTextPainted();
+  bool ImagePainted(const void* frame) const;
+  void SetImagePainted();
 
   // Returns displayItemList added using createAndAppend() since beginning or
   // the last commitNewDisplayItems(). Use with care.
@@ -211,14 +211,14 @@ class PLATFORM_EXPORT PaintController {
 
   bool LastDisplayItemIsSubsequenceEnd() const;
 
+  void BeginFrame(const void* frame);
+  void EndFrame(const void* frame);
+
  protected:
   PaintController()
       : new_display_item_list_(0),
         construction_disabled_(false),
         subsequence_caching_disabled_(false),
-        first_painted_(false),
-        text_painted_(false),
-        image_painted_(false),
         skipping_cache_count_(0),
         num_cached_new_items_(0),
         current_cached_subsequence_begin_index_in_new_list_(kNotFound),
@@ -341,12 +341,15 @@ class PLATFORM_EXPORT PaintController {
   bool subsequence_caching_disabled_;
 
   // The following fields indicate that this PaintController has ever had
-  // first-paint, text or image painted. They are never reset to false.
-  // First-paint is defined in https://github.com/WICG/paint-timing. It excludes
-  // default background paint.
-  bool first_painted_;
-  bool text_painted_;
-  bool image_painted_;
+  // first-paint, text or image painted for each frame. They are never reset to
+  // false. First-paint is defined in https://github.com/WICG/paint-timing. It
+  // excludes default background paint.
+  HashMap<const void*, bool> first_painted_;
+  HashMap<const void*, bool> text_painted_;
+  HashMap<const void*, bool> image_painted_;

[Xianzhu, 2017/05/08 22:44:46]

HashMap is much slower than direct field to access, so this will affect
PaintController performance.

How about the following method:

  struct FrameFirstPaint {
    FrameFirstPaint(const void* frame) : frame(frame), ... {}

    const void* frame;
    bool first_painted : 1;
    bool text_painted : 1;
    bool image_painted : 1;
  };

  Vector<FrameAndFirstPaint> frame_first_paints_;

void SetFirstPainted() {
  frame_first_paints_.back().first_painted = true;
}

FrameFirstPaint EndFrame() {
  auto result = frame_first_paints_.back();
  frame_first_paints_.pop_back();
  return result;
}

[Zhen Wang, 2017/05/09 20:13:43]

Done.

+
+  // A stack recording current frames.
+  Vector<const void*> current_frames_;
 
   int skipping_cache_count_;