Notify paint for each frame

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

 // 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.
 
 #ifndef PaintController_h
 #define PaintController_h
 
 #include <memory>
 #include <utility>
 #include "platform/PlatformExport.h"
@@ skipping 15 matching lines @@
 #include "platform/wtf/PtrUtil.h"
 #include "platform/wtf/Vector.h"
 #include "third_party/skia/include/core/SkRefCnt.h"
 
 namespace blink {
 
 static const size_t kInitialDisplayItemListCapacityBytes = 512;
 
 template class RasterInvalidationTrackingMap<const PaintChunk>;
 
+// FrameFirstPaint stores first-paint, text or image painted for the
+// corresponding frame. They are never reset to false. First-paint is defined in
+// https://github.com/WICG/paint-timing. It excludes default background paint.
+struct FrameFirstPaint {
+  FrameFirstPaint(const void* frame)
+      : frame(frame),
+        first_painted(false),
+        text_painted(false),
+        image_painted(false) {}
+
+  const void* frame;
+  bool first_painted : 1;
+  bool text_painted : 1;
+  bool image_painted : 1;
+};
+
 // Responsible for processing display items as they are produced, and producing
 // a final paint artifact when complete. This class includes logic for caching,
 // cache invalidation, and merging.
 class PLATFORM_EXPORT PaintController {
   WTF_MAKE_NONCOPYABLE(PaintController);
   USING_FAST_MALLOC(PaintController);
 
  public:
   static std::unique_ptr<PaintController> Create() {
     return WTF::WrapUnique(new PaintController());
@@ skipping 108 matching lines @@
   void SetDisplayItemConstructionIsDisabled(const bool disable) {
     construction_disabled_ = disable;
   }
   bool SubsequenceCachingIsDisabled() const {
     return subsequence_caching_disabled_;
   }
   void SetSubsequenceCachingIsDisabled(bool disable) {
     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; }
+  void SetFirstPainted();
+  void SetTextPainted();
+  void SetImagePainted();
 
   // Returns displayItemList added using createAndAppend() since beginning or
   // the last commitNewDisplayItems(). Use with care.
   DisplayItemList& NewDisplayItemList() { return new_display_item_list_; }
 
   void AppendDebugDrawingAfterCommit(
       const DisplayItemClient&,
       sk_sp<PaintRecord>,
       const LayoutSize& offset_from_layout_object);
 
@@ skipping 24 matching lines @@
   void BeginSubsequence(const DisplayItemClient& client) {
     current_subsequence_clients_.push_back(&client);
     BeginShouldKeepAlive(client);
   }
 
   void EndSubsequence() { current_subsequence_clients_.pop_back(); }
 #endif
 
   bool LastDisplayItemIsSubsequenceEnd() const;
 
+  void BeginFrame(const void* frame);
+  FrameFirstPaint 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),
 #ifndef NDEBUG
         num_sequential_matches_(0),
         num_out_of_order_matches_(0),
         num_indexed_items_(0),
 #endif
         under_invalidation_checking_begin_(0),
         under_invalidation_checking_end_(0),
         last_cached_subsequence_end_(0) {
     ResetCurrentListIndices();
     SetTracksRasterInvalidations(
         RuntimeEnabledFeatures::paintUnderInvalidationCheckingEnabled());
+    frame_first_paints_.push_back(FrameFirstPaint(nullptr));

[Xianzhu, 2017/05/09 23:13:08]

Please add a comment to explain the reason.

[Zhen Wang, 2017/05/09 23:26:24]

Done.

   }
 
  private:
   friend class PaintControllerTestBase;
   friend class PaintControllerPaintTestBase;
 
   bool LastDisplayItemIsNoopBegin() const;
 
   void EnsureNewDisplayItemListInitialCapacity() {
     if (new_display_item_list_.IsEmpty()) {
@@ skipping 87 matching lines @@
   Vector<size_t> items_moved_into_new_list_;
 
   // Allows display item construction to be disabled to isolate the costs of
   // construction in performance metrics.
   bool construction_disabled_;
 
   // Allows subsequence caching to be disabled to test the cost of display item
   // caching.
   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_;
+  // A stack recording current frames' first paints.
+  Vector<FrameFirstPaint> frame_first_paints_;
 
   int skipping_cache_count_;
 
   int num_cached_new_items_;
 
   // Stores indices to valid cacheable display items in
   // m_currentPaintArtifact.displayItemList() that have not been matched by
   // requests of cached display items (using useCachedDrawingIfPossible() and
   // useCachedSubsequenceIfPossible()) during sequential matching. The indexed
   // items will be matched by later out-of-order requests of cached display
@@ skipping 64 matching lines @@
   CachedSubsequenceMap new_cached_subsequences_;
   size_t last_cached_subsequence_end_;
 
   FRIEND_TEST_ALL_PREFIXES(PaintControllerTest, CachedSubsequenceSwapOrder);
   FRIEND_TEST_ALL_PREFIXES(PaintControllerTest, CachedNestedSubsequenceUpdate);
 };
 
 }  // namespace blink
 
 #endif  // PaintController_h