cc: DelegatedRenderer layer needs a surface if rotated.

cc/layer_tree_host_common.cc

Index: cc/layer_tree_host_common.cc
diff --git a/cc/layer_tree_host_common.cc b/cc/layer_tree_host_common.cc
index 5746dde48523e81f92ddd34f97fe2486988c907a..f4bf6341ad4f770176ff0528278fcdb6921a3f53 100644
--- a/cc/layer_tree_host_common.cc
+++ b/cc/layer_tree_host_common.cc
@@ -132,7 +132,7 @@ static bool isSurfaceBackFaceVisible(LayerType* layer, const gfx::Transform& dra
 template<typename LayerType>
 static inline bool layerClipsSubtree(LayerType* layer)
 {
-    return layer->masksToBounds() || layer->maskLayer();
+    return layer->masksToBounds() || layer->maskLayer() || layer->hasDelegatedContent();

[piman, 2013/01/19 02:39:09]

I wonder if this could have a bad side effect if we add a child to a DRL (not
that we'd do that normally in Aura, but with the browser tag, I dunno?), because
while it wants to clip the render passes, it may not necessarily want to clip
child layers.

[danakj, 2013/01/19 02:43:00]

In my mind the DRLayer should never have any children.

With browser tag, it should have the parent compositor as the renderer, so the
DRLayer would include all the quads from the renderer and any browser tags.
Otherwise it's impossible to do things like correct z order.

SG?

 }
 
 template<typename LayerType>
@@ -302,8 +302,7 @@ static bool subtreeShouldRenderToSeparateSurface(LayerType* layer, bool axisAlig
     // subtree overlap. But checking layer overlaps is unnecessarily costly so
     // instead we conservatively create a surface whenever at least two layers
     // draw content for this subtree.
-    bool atLeastTwoLayersInSubtreeDrawContent = layer->hasDelegatedContent() ||
-        (numDescendantsThatDrawContent > 0 && (layer->drawsContent() || numDescendantsThatDrawContent > 1));
+    bool atLeastTwoLayersInSubtreeDrawContent = numDescendantsThatDrawContent > 0 && (layer->drawsContent() || numDescendantsThatDrawContent > 1);
 
     if (layer->opacity() != 1 && !layer->preserves3D() && atLeastTwoLayersInSubtreeDrawContent) {
         TRACE_EVENT_INSTANT0("cc", "LayerTreeHostCommon::requireSurface opacity");
@@ -495,6 +494,15 @@ static inline void removeSurfaceForEarlyExit(LayerType* layerToRemove, LayerList
 template<typename LayerType>
 static void preCalculateMetaInformation(LayerType* layer)
 {
+    if (layer->hasDelegatedContent()) {
+        // Layers with delegated content need to be treated as if they have as many children as the number
+        // of layers they own delegated quads for. Since we don't know this number right now, we choose
+        // one that acts like infinity for our purposes.
+        layer->drawProperties().num_descendants_that_draw_content = 1000;
+        layer->drawProperties().descendants_can_clip_selves = false;
+        return;
+    }
+
     int numDescendantsThatDrawContent = 0;
     bool descendantsCanClipSelves = true;
     bool sublayerTransformPreventsClip = !layer->sublayerTransform().IsPositiveScaleOrTranslation();