Skip drawing unsupported layers in forced software mode

cc/layers/texture_layer_impl.cc

Index: cc/layers/texture_layer_impl.cc
diff --git a/cc/layers/texture_layer_impl.cc b/cc/layers/texture_layer_impl.cc
index 17f6c480a39afcbce87816f66005f4d78919f0e6..622ddba8f7d96e559edfd7bba91b0e5d64fe2e92 100644
--- a/cc/layers/texture_layer_impl.cc
+++ b/cc/layers/texture_layer_impl.cc
@@ -63,14 +63,20 @@ void TextureLayerImpl::PushPropertiesTo(LayerImpl* layer) {
   }
 }
 
-void TextureLayerImpl::WillDraw(ResourceProvider* resource_provider) {
-  if (uses_mailbox_ || !texture_id_)
-    return;
-  DCHECK(!external_texture_resource_);
-  external_texture_resource_ =
-      resource_provider->CreateResourceFromExternalTexture(
-          GL_TEXTURE_2D,
-          texture_id_);
+bool TextureLayerImpl::WillDraw(DrawMode draw_mode,
+                                ResourceProvider* resource_provider) {
+  if (!texture_id_ ||
+      draw_mode == DRAW_MODE_RESOURCELESS_SOFTWARE)
+    return false;

[piman, 2013/05/31 00:48:15]

still nak, because if uses_mailbox_, then texture_id_ will be 0.

Basically you have 2 modes (mailbox and non-mailbox).

In the mailbox mode, the resource is created in DidBecomeActive, if the mailbox
is not empty. If it's empty, we leave the resource as 0 and we skip drawing in
AppendQuads.

In the texture mode, the resource is created here if the texture is non-0,
otherwise we leave the resource as 0 and skip drawing in AppendQuads

You can refactor this as:
if (draw_mode == DRAW_MODE_RESOURCELESS_SOFTWARE)
  return false;
if (!uses_mailbox_) {
  DCHECK(!external_texture_resource_);
  external_texture_resource_ =
resource_provider->CreateResourceFromExternalTexture(
          GL_TEXTURE_2D,
          texture_id_);
}
return LayerImpl::WillDraw(draw_mode, resource_provider) &&
!!external_texture_resource_;

And then leave out the early return in AppendQuads.

[boliu, 2013/05/31 02:50:07]

Second try! Should be fixed now. The second if condition should be
(!uses_mailbox_ && texture_id_). Also added a test just for this.

+
+  if (!uses_mailbox_) {
+    DCHECK(!external_texture_resource_);
+    external_texture_resource_ =
+        resource_provider->CreateResourceFromExternalTexture(
+            GL_TEXTURE_2D,
+            texture_id_);
+  }
+  return LayerImpl::WillDraw(draw_mode, resource_provider);
 }
 
 void TextureLayerImpl::AppendQuads(QuadSink* quad_sink,
@@ -103,6 +109,7 @@ void TextureLayerImpl::AppendQuads(QuadSink* quad_sink,
 }
 
 void TextureLayerImpl::DidDraw(ResourceProvider* resource_provider) {
+  LayerImpl::DidDraw(resource_provider);
   if (uses_mailbox_ || !external_texture_resource_)
     return;
   // FIXME: the following assert will not be true when sending resources to a