Support subtitles for native fullscreen video

Source/core/rendering/RenderLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 Apple 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 11 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
 
 #include "core/rendering/RenderLayerCompositor.h"
 
 #include "CSSPropertyNames.h"
 #include "HTMLNames.h"
+#include "RuntimeEnabledFeatures.h"
 #include "core/dom/NodeList.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLIFrameElement.h"
 #include "core/html/canvas/CanvasRenderingContext.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/page/Chrome.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/Frame.h"
 #include "core/page/FrameView.h"
 #include "core/page/Page.h"
@@ skipping 180 matching lines @@
     , m_compositedLayerCount(0)
     , m_showRepaintCounter(false)
     , m_reevaluateCompositingAfterLayout(false)
     , m_compositing(false)
     , m_compositingLayersNeedRebuild(false)
     , m_forceCompositingMode(false)
     , m_inPostLayoutUpdate(false)
     , m_needsUpdateCompositingRequirementsState(false)
     , m_isTrackingRepaints(false)
     , m_rootLayerAttachment(RootLayerUnattached)
+    , m_currentFullscreenRenderer(0)
 #if !LOG_DISABLED
     , m_rootLayerUpdateCount(0)
     , m_obligateCompositedLayerCount(0)
     , m_secondaryCompositedLayerCount(0)
     , m_obligatoryBackingStoreBytes(0)
     , m_secondaryBackingStoreBytes(0)
 #endif
 {
 }
 
@@ skipping 197 matching lines @@
     if (needHierarchyUpdate) {
         // Update the hierarchy of the compositing layers.
         Vector<GraphicsLayer*> childList;
         {
             TRACE_EVENT0("blink_rendering", "RenderLayerCompositor::rebuildCompositingLayerTree");
             rebuildCompositingLayerTree(updateRoot, childList, 0);
         }
 
         // Host the document layer in the RenderView's root layer.
         if (isFullUpdate) {
+            if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && m_currentFullscreenRenderer && m_currentFullscreenRenderer->isMedia()) {
+                RenderLayerModelObject* renderer = toRenderLayerModelObject(m_currentFullscreenRenderer);

[esprehn, 2013/09/13 02:46:07]

SVG elements can never be full screen? They're not RenderLayerMOdelObjects so if
they can this doesn't seem safe.

[trchen, 2013/09/13 05:14:58]

This special code path only applies for RenderMedia. SVG elements use the usual
fullscreen code path.

+                RenderLayerBacking* backing = renderer->layer() ? renderer->layer()->backing() : 0;

[esprehn, 2013/09/13 02:46:07]

You should just add a method to RenderLayerModelObject like backing() and get
rid of the ternary here.

[trchen, 2013/09/13 05:14:58]

Done.

+                if (backing) {
+                    childList.clear();
+                    childList.append(backing->graphicsLayer());
+                }
+            }
             // Even when childList is empty, don't drop out of compositing mode if there are
             // composited layers that we didn't hit in our traversal (e.g. because of visibility:hidden).
             if (childList.isEmpty() && !hasAnyAdditionalCompositedLayers(updateRoot))
                 destroyRootLayer();
             else
                 m_rootContentLayer->setChildren(childList);
         }
     } else if (needGeometryUpdate) {
         // We just need to do a geometry update. This is only used for position:fixed scrolling;
         // most of the time, geometry is updated via RenderLayer::styleChanged().
@@ skipping 1369 matching lines @@
         return false;
 
     RenderStyle* style = renderer->style();
     // Note that we ask the renderer if it has a transform, because the style may have transforms,
     // but the renderer may be an inline that doesn't suppport them.
     return renderer->hasTransform() && style->transform().has3DOperation();
 }
 
 bool RenderLayerCompositor::requiresCompositingForVideo(RenderObject* renderer) const
 {
+    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && renderer->isVideo() && renderer == m_currentFullscreenRenderer)
+        return true;
+
     if (!(m_compositingTriggers & ChromeClient::VideoTrigger))
         return false;
 
     if (renderer->isVideo()) {
         RenderVideo* video = toRenderVideo(renderer);
         return video->shouldDisplayVideo() && canAccelerateVideoRendering(video);
     }
     return false;
 }
 
@@ skipping 906 matching lines @@
         name = "Frame Clipping Layer";
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "Frame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
+void RenderLayerCompositor::setCurrentFullscreenRenderer(RenderObject* renderer)
+{
+    if (renderer == m_currentFullscreenRenderer)
+        return;
+    m_currentFullscreenRenderer = renderer;

[esprehn, 2013/09/13 02:46:07]

I'm not a fan of keeping RenderObjects across frames or at all like this. I'd
rather you kept a RefPtr to a Node and called renderer() whenever you needed it.
That way you can never have a stale renderer.

[trchen, 2013/09/13 05:14:58]

That is one alternative way I have thought about. My concern is that it would be
a layer violation for the core/rendering to know anything about core/dom.
Actually I think keeping a RenderObject is safe. The only place we
construct/destruct render object is in Element::attach/detach, and I believe it
is guaranteed by design.

If in doubt, we can guard this code path with
REF::overlayFullscreenVideoEnabled() too, so we have some damage control if this
approach is in fact problematic.

+    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && (!renderer || renderer->isVideo()))
+        setCompositingLayersNeedRebuild(true);
+}
+
 } // namespace WebCore