Skip drawing unsupported layers in forced software mode

cc/layers/layer_impl.h

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_LAYERS_LAYER_IMPL_H_
 #define CC_LAYERS_LAYER_IMPL_H_
 
 #include <string>
 
 #include "base/logging.h"
@@ skipping 31 matching lines @@
 class LayerTreeHostImpl;
 class LayerTreeImpl;
 class QuadSink;
 class Renderer;
 class ScrollbarAnimationController;
 class ScrollbarLayerImpl;
 class Layer;
 
 struct AppendQuadsData;
 
+enum DrawMode {
+  DRAW_MODE_NONE,
+  DRAW_MODE_HARDWARE,
+  DRAW_MODE_SOFTWARE,
+  DRAW_MODE_RESOURCELESS_SOFTWARE
+};
+
 class CC_EXPORT LayerImpl : LayerAnimationValueObserver {
  public:
   static scoped_ptr<LayerImpl> Create(LayerTreeImpl* tree_impl, int id) {
     return make_scoped_ptr(new LayerImpl(tree_impl, id));
   }
 
   virtual ~LayerImpl();
 
   int id() const { return layer_id_; }
 
@@ skipping 30 matching lines @@
 
   bool has_mask() const { return mask_layer_; }
   bool has_replica() const { return replica_layer_; }
   bool replica_has_mask() const {
     return replica_layer_ && (mask_layer_ || replica_layer_->mask_layer_);
   }
 
   LayerTreeImpl* layer_tree_impl() const { return layer_tree_impl_; }
 
   scoped_ptr<SharedQuadState> CreateSharedQuadState() const;
-  // WillDraw must be called before AppendQuads. If WillDraw is called,
+  // WillDraw must be called before AppendQuads. If WillDraw returns false,
+  // AppendQuads and DidDraw will not be called. If WillDraw returns true,
   // DidDraw is guaranteed to be called before another WillDraw or before
   // the layer is destroyed. To enforce this, any class that overrides
-  // WillDraw/DqidDraw must call the base class version.
-  virtual void WillDraw(ResourceProvider* resource_provider);
+  // WillDraw/DidDraw must call the base class version only if WillDraw
+  // returns true.
+  virtual bool WillDraw(DrawMode draw_mode,
+                        ResourceProvider* resource_provider);
   virtual void AppendQuads(QuadSink* quad_sink,
                            AppendQuadsData* append_quads_data) {}
   virtual void DidDraw(ResourceProvider* resource_provider);
 
   virtual ResourceProvider::ResourceId ContentsResourceId() const;
 
   virtual bool HasDelegatedContent() const;
   virtual bool HasContributingDelegatedRenderPasses() const;
   virtual RenderPass::Id FirstContributingRenderPassId() const;
   virtual RenderPass::Id NextContributingRenderPassId(RenderPass::Id id) const;
@@ skipping 406 matching lines @@
   float draw_depth_;
 
   // Debug layer name.
   std::string debug_name_;
   CompositingReasons compositing_reasons_;
 
   WebKit::WebFilterOperations filters_;
   WebKit::WebFilterOperations background_filters_;
   skia::RefPtr<SkImageFilter> filter_;
 
-#ifndef NDEBUG
-  bool between_will_draw_and_did_draw_;
-#endif
+ protected:
+  DrawMode current_draw_mode_;
 
+ private:
   // Rect indicating what was repainted/updated during update.
   // Note that plugin layers bypass this and leave it empty.
   // Uses layer's content space.
   gfx::RectF update_rect_;
 
   // Manages animations for this layer.
   scoped_refptr<LayerAnimationController> layer_animation_controller_;
 
   // Manages scrollbars for this layer
   scoped_ptr<ScrollbarAnimationController> scrollbar_animation_controller_;
 
   // Weak pointers to this layer's scrollbars, if it has them. Updated during
   // tree synchronization.
   ScrollbarLayerImpl* horizontal_scrollbar_layer_;
   ScrollbarLayerImpl* vertical_scrollbar_layer_;
 
   ScopedPtrVector<CopyOutputRequest> copy_requests_;
 
   // Group of properties that need to be computed based on the layer tree
   // hierarchy before layers can be drawn.
   DrawProperties<LayerImpl, RenderSurfaceImpl> draw_properties_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_IMPL_H_