Support subtitles for native fullscreen video

Source/core/rendering/RenderLayerCompositor.cpp

Index: Source/core/rendering/RenderLayerCompositor.cpp
diff --git a/Source/core/rendering/RenderLayerCompositor.cpp b/Source/core/rendering/RenderLayerCompositor.cpp
index c5e25a56d6742463a17fb08058b10d47813a941c..38427adab478b4de752938c037cf753b89ca671b 100644
--- a/Source/core/rendering/RenderLayerCompositor.cpp
+++ b/Source/core/rendering/RenderLayerCompositor.cpp
@@ -29,6 +29,7 @@
 
 #include "CSSPropertyNames.h"
 #include "HTMLNames.h"
+#include "RuntimeEnabledFeatures.h"
 #include "core/dom/NodeList.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLIFrameElement.h"
@@ -229,6 +230,7 @@ RenderLayerCompositor::RenderLayerCompositor(RenderView* renderView)
     , m_needsUpdateCompositingRequirementsState(false)
     , m_isTrackingRepaints(false)
     , m_rootLayerAttachment(RootLayerUnattached)
+    , m_currentFullscreenRenderer(0)
 #if !LOG_DISABLED
     , m_rootLayerUpdateCount(0)
     , m_obligateCompositedLayerCount(0)
@@ -242,6 +244,7 @@ RenderLayerCompositor::RenderLayerCompositor(RenderView* renderView)
 RenderLayerCompositor::~RenderLayerCompositor()
 {
     ASSERT(m_rootLayerAttachment == RootLayerUnattached);
+    ASSERT(!m_currentFullscreenRenderer);
 }
 
 void RenderLayerCompositor::enableCompositingMode(bool enable /* = true */)
@@ -446,6 +449,14 @@ void RenderLayerCompositor::updateCompositingLayers(CompositingUpdateType update
 
         // 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);
+                RenderLayerBacking* backing = renderer->backing();
+                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))
@@ -1853,6 +1864,9 @@ bool RenderLayerCompositor::requiresCompositingForTransform(RenderObject* render
 
 bool RenderLayerCompositor::requiresCompositingForVideo(RenderObject* renderer) const
 {
+    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && renderer->isVideo() && renderer == m_currentFullscreenRenderer)
+        return true;
+
     if (!(m_compositingTriggers & ChromeClient::VideoTrigger))
         return false;
 
@@ -2752,4 +2766,21 @@ String RenderLayerCompositor::debugName(const GraphicsLayer* graphicsLayer)
     return name;
 }
 
+void RenderLayerCompositor::setCurrentFullscreenRenderer(RenderObject* renderer)
+{
+    if (renderer == m_currentFullscreenRenderer)
+        return;
+#ifndef NDEBUG
+    if (m_currentFullscreenRenderer)
+        m_currentFullscreenRenderer->setIsCurrentFullscreen(false);
+#endif
+    m_currentFullscreenRenderer = renderer;
+#ifndef NDEBUG
+    if (m_currentFullscreenRenderer)
+        m_currentFullscreenRenderer->setIsCurrentFullscreen(true);
+#endif
+    if (RuntimeEnabledFeatures::overlayFullscreenVideoEnabled() && (!renderer || renderer->isVideo()))
+        setCompositingLayersNeedRebuild(true);
+}
+
 } // namespace WebCore