Slimming Paint phase 2 compositing algorithm plumbing & skeleton display list API.

Source/platform/graphics/ContentLayerDelegate.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
@@ skipping 15 matching lines @@
 
 #include "platform/graphics/ContentLayerDelegate.h"
 
 #include "platform/EventTracer.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "platform/TraceEvent.h"
 #include "platform/TracedValue.h"
 #include "platform/geometry/IntRect.h"
 #include "platform/graphics/GraphicsContext.h"
 #include "platform/graphics/paint/DisplayItemList.h"
+#include "platform/graphics/paint/DisplayList.h"
 #include "platform/transforms/AffineTransform.h"
 #include "platform/transforms/TransformationMatrix.h"
 #include "public/platform/WebDisplayItemList.h"
 #include "public/platform/WebFloatRect.h"
 #include "public/platform/WebRect.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "third_party/skia/include/core/SkPicture.h"
 #include "third_party/skia/include/core/SkPictureRecorder.h"
 
 namespace blink {
@@ skipping 37 matching lines @@
 }
 
 void ContentLayerDelegate::paintContents(
     WebDisplayItemList* webDisplayItemList, const WebRect& clip,
     WebContentLayerClient::PaintingControlSetting paintingControl)
 {
     TRACE_EVENT1("blink,benchmark", "ContentLayerDelegate::paintContents", "clip_rect", toTracedValue(clip));
 
     ASSERT(RuntimeEnabledFeatures::slimmingPaintEnabled());
 
+    if (RuntimeEnabledFeatures::slimmingPaintCompositorLayerizationEnabled()) {
+        // Scrollbars for the root frame stil paint in the old way, and don't have a displayList().
+        if (m_painter->displayList()) {
+            for (unsigned i = 0; i < m_painter->displayList()->size(); i++) {
+                m_painter->displayList()->displayItemInternal(i).appendToWebDisplayItemList(webDisplayItemList);

[weiliangc, 2015/07/24 19:17:15]

Is it possible that this line changes the order of DisplayItems in the global
DisplayItemList, thus invalidate the indices we saved in the offset of
WebDisplayList on each layer?

Since we'd have to convert DisplayItem to WebDisplayItem, maybe we could let
Layers own the partial WebDisplayItemList? WDYT?

[chrishtr, 2015/07/24 19:27:21]

I think we should end up with representation in which there is exactly one
display list array that everyone on the same thread shares. The copying in this
CL is necessary only before the blink/cc merge.

As for whether there is a bug in this sample implementation...maybe. :)

+            }
+            return;
+        }
+    }
+
     DisplayItemList* displayItemList = m_painter->displayItemList();
     ASSERT(displayItemList);
     displayItemList->setDisplayItemConstructionIsDisabled(
         paintingControl == WebContentLayerClient::DisplayListConstructionDisabled);
 
     // We also disable caching when Painting or Construction are disabled. In both cases we would like
     // to compare assuming the full cost of recording, not the cost of re-using cached content.
     if (paintingControl != WebContentLayerClient::PaintDefaultBehavior)
         displayItemList->invalidateAll();
 
     GraphicsContext::DisabledMode disabledMode = GraphicsContext::NothingDisabled;
     if (paintingControl == WebContentLayerClient::DisplayListPaintingDisabled
         || paintingControl == WebContentLayerClient::DisplayListConstructionDisabled)
         disabledMode = GraphicsContext::FullyDisabled;
     GraphicsContext context(displayItemList, disabledMode);
 
     m_painter->paint(context, clip);
 
     displayItemList->commitNewDisplayItemsAndAppendToWebDisplayItemList(webDisplayItemList);
 }
 
 size_t ContentLayerDelegate::approximateUnsharedMemoryUsage() const
 {
     return m_painter->displayItemList()->approximateUnsharedMemoryUsage();
 }
 
+const WebDisplayList* ContentLayerDelegate::displayList() const
+{
+    return m_painter->displayList();
+}
+
+const WebDisplayItemTransformTree* ContentLayerDelegate::transformTree() const
+{
+    return 0;
+}
+
 } // namespace blink