Remove hit-testing-only RSLL entries

As of https://codereview.chromium.org/266913021/ we no longer hit test
via the RSLL; we walk the tree instead. This means we can remove the
machinery added to allow hidden layers to appear in the RSLL for hit
testing purposes.

This is essentially a revert of https://codereview.chromium.org/25712004

R=danakj@chromium.org
BUG=None

Review URL: https://codereview.chromium.org/289973003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@270742 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 6 insertions, 197 deletions

diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index e284014..67fe68b 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -1001,7 +1001,7 @@ void LayerTreeHost::PaintLayerContents(
     if (it.represents_target_render_surface()) {
       PaintMasksForRenderSurface(
           *it, queue, did_paint_content, need_more_updates);
-    } else if (it.represents_itself() && it->DrawsContent()) {
+    } else if (it.represents_itself()) {
       DCHECK(!it->paint_properties().bounds.IsEmpty());
       *did_paint_content |= it->Update(queue, &occlusion_tracker);
       *need_more_updates |= it->NeedMoreUpdates();
diff --git a/cc/trees/layer_tree_host_common.cc b/cc/trees/layer_tree_host_common.cc
index a9af3ef..34f4553 100644
--- a/cc/trees/layer_tree_host_common.cc
+++ b/cc/trees/layer_tree_host_common.cc
@@ -431,10 +431,10 @@ static bool LayerShouldBeSkipped(LayerType* layer, bool layer_is_drawn) {
   // Layers can be skipped if any of these conditions are met.
   //   - is not drawn due to it or one of its ancestors being hidden (or having
   //     no copy requests).
+  //   - does not draw content.
+  //   - is transparent.
   //   - has empty bounds
   //   - the layer is not double-sided, but its back face is visible.
-  //   - is transparent
-  //   - does not draw content and does not participate in hit testing.
   //
   // Some additional conditions need to be computed at a later point after the
   // recursion is finished.
@@ -448,7 +448,7 @@ static bool LayerShouldBeSkipped(LayerType* layer, bool layer_is_drawn) {
   if (!layer_is_drawn)
     return true;
 
-  if (layer->bounds().IsEmpty())
+  if (!layer->DrawsContent() || layer->bounds().IsEmpty())
     return true;
 
   LayerType* backface_test_layer = layer;
@@ -465,13 +465,6 @@ static bool LayerShouldBeSkipped(LayerType* layer, bool layer_is_drawn) {
       IsLayerBackFaceVisible(backface_test_layer))
     return true;
 
-  // The layer is visible to events.  If it's subject to hit testing, then
-  // we can't skip it.
-  bool can_accept_input = !layer->touch_event_handler_region().IsEmpty() ||
-      layer->have_wheel_event_handlers();
-  if (!layer->DrawsContent() && !can_accept_input)
-    return true;
-
   return false;
 }
 
@@ -507,7 +500,6 @@ static inline bool SubtreeShouldBeSkipped(LayerImpl* layer,
   // The opacity of a layer always applies to its children (either implicitly
   // via a render surface or explicitly if the parent preserves 3D), so the
   // entire subtree can be skipped if this layer is fully transparent.
-  // TODO(sad): Don't skip layers used for hit testing crbug.com/295295.
   return !layer->opacity();
 }
 
@@ -531,7 +523,6 @@ static inline bool SubtreeShouldBeSkipped(Layer* layer, bool layer_is_drawn) {
   // In particular, it should not cause the subtree to be skipped.
   // Similarly, for layers that might animate opacity using an impl-only
   // animation, their subtree should also not be skipped.
-  // TODO(sad): Don't skip layers used for hit testing crbug.com/295295.
   return !layer->opacity() && !layer->OpacityIsAnimating() &&
          !layer->OpacityCanAnimateOnImplThread();
 }
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index b51d6f9..eb2ba96 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -825,7 +825,7 @@ DrawResult LayerTreeHostImpl::CalculateRenderPasses(
                                        contributing_render_pass,
                                        occlusion_tracker,
                                        &append_quads_data);
-    } else if (it.represents_itself() && it->DrawsContent() &&
+    } else if (it.represents_itself() &&
                !it->visible_content_rect().IsEmpty()) {
       bool occluded = occlusion_tracker.Occluded(it->render_target(),
                                                  it->visible_content_rect(),
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index 52ac0f6..888b0f6 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -4645,41 +4645,6 @@ class LayerTreeHostTestMemoryLimits : public LayerTreeHostTest {
 
 SINGLE_AND_MULTI_THREAD_NOIMPL_TEST_F(LayerTreeHostTestMemoryLimits);
 
-class LayerTreeHostTestNoQuadsForEmptyLayer : public LayerTreeHostTest {
- protected:
-  virtual void SetupTree() OVERRIDE {
-    LayerTreeHostTest::SetupTree();
-    root_layer_ = FakeContentLayer::Create(&client_);
-    root_layer_->SetBounds(gfx::Size(10, 10));
-    root_layer_->SetIsDrawable(false);
-    root_layer_->SetHaveWheelEventHandlers(true);
-    layer_tree_host()->SetRootLayer(root_layer_);
-    LayerTreeHostTest::SetupTree();
-  }
-
-  virtual void BeginTest() OVERRIDE { PostSetNeedsCommitToMainThread(); }
-
-  virtual void DidActivateTreeOnThread(LayerTreeHostImpl* impl) OVERRIDE {
-    FakeContentLayerImpl* layer_impl =
-        static_cast<FakeContentLayerImpl*>(impl->RootLayer());
-    EXPECT_FALSE(layer_impl->DrawsContent());
-    EXPECT_EQ(0u, layer_impl->append_quads_count());
-  }
-
-  virtual void DidCommit() OVERRIDE {
-    // The layer is not drawable, so it should not be updated.
-    EXPECT_EQ(0u, root_layer_->update_count());
-    EndTest();
-  }
-  virtual void AfterTest() OVERRIDE {}
-
- private:
-  FakeContentLayerClient client_;
-  scoped_refptr<FakeContentLayer> root_layer_;
-};
-
-SINGLE_AND_MULTI_THREAD_TEST_F(LayerTreeHostTestNoQuadsForEmptyLayer);
-
 }  // namespace
 
 class LayerTreeHostTestSetMemoryPolicyOnLostOutputSurface
diff --git a/cc/trees/layer_tree_impl.h b/cc/trees/layer_tree_impl.h
index 5b740c3..d27e1e4 100644
--- a/cc/trees/layer_tree_impl.h
+++ b/cc/trees/layer_tree_impl.h
@@ -295,8 +295,7 @@ class CC_EXPORT LayerTreeImpl {
   // Persisted state for non-impl-side-painting.
   int scrolling_layer_id_from_previous_tree_;
 
-  // List of visible or hit-testable layers for the most recently prepared
-  // frame. Used for rendering and input event hit testing.
+  // List of visible layers for the most recently prepared frame.
   LayerImplList render_surface_layer_list_;
 
   bool use_gpu_rasterization_;
diff --git a/cc/trees/layer_tree_impl_unittest.cc b/cc/trees/layer_tree_impl_unittest.cc
index b27a06e..4a8259e 100644
--- a/cc/trees/layer_tree_impl_unittest.cc
+++ b/cc/trees/layer_tree_impl_unittest.cc
@@ -1185,110 +1185,6 @@ TEST_F(LayerTreeImplTest, HitTestingForMultipleLayerLists) {
   EXPECT_EQ(4, result_layer->id());
 }
 
-TEST_F(LayerTreeImplTest, HitTestingForEmptyLayers) {
-  // Layer 1 - root
-  scoped_ptr<LayerImpl> root = LayerImpl::Create(host_impl().active_tree(), 1);
-  gfx::Transform identity_matrix;
-  gfx::PointF anchor;
-  gfx::PointF position;
-  gfx::Size bounds(100, 100);
-  SetLayerPropertiesForTesting(
-      root.get(), identity_matrix, anchor, position, bounds, true, false);
-  root->SetDrawsContent(true);
-
-  {
-    // Layer 2 - empty: drawsContent=false
-    gfx::PointF position(10.f, 10.f);
-    gfx::Size bounds(30, 30);
-    scoped_ptr<LayerImpl> empty_layer =
-        LayerImpl::Create(host_impl().active_tree(), 2);
-    SetLayerPropertiesForTesting(empty_layer.get(),
-                                 identity_matrix,
-                                 anchor,
-                                 position,
-                                 bounds,
-                                 true,
-                                 false);
-
-    empty_layer->SetDrawsContent(false);
-    root->AddChild(empty_layer.Pass());
-  }
-
-  {
-    // Layer 3 - empty, but has touch handler
-    gfx::PointF position(10.f, 60.f);
-    gfx::Size bounds(30, 30);
-    scoped_ptr<LayerImpl> test_layer =
-        LayerImpl::Create(host_impl().active_tree(), 3);
-    SetLayerPropertiesForTesting(test_layer.get(),
-                                 identity_matrix,
-                                 anchor,
-                                 position,
-                                 bounds,
-                                 true,
-                                 false);
-
-    test_layer->SetDrawsContent(false);
-    Region touch_handler_region(gfx::Rect(10, 10, 10, 10));
-    test_layer->SetTouchEventHandlerRegion(touch_handler_region);
-    root->AddChild(test_layer.Pass());
-  }
-
-  {
-    // Layer 4 - empty, but has mousewheel handler
-    gfx::PointF position(60.f, 60.f);
-    gfx::Size bounds(30, 30);
-    scoped_ptr<LayerImpl> test_layer =
-        LayerImpl::Create(host_impl().active_tree(), 4);
-    SetLayerPropertiesForTesting(test_layer.get(),
-                                 identity_matrix,
-                                 anchor,
-                                 position,
-                                 bounds,
-                                 true,
-                                 false);
-
-    test_layer->SetDrawsContent(false);
-    test_layer->SetHaveWheelEventHandlers(true);
-    root->AddChild(test_layer.Pass());
-  }
-
-  host_impl().SetViewportSize(root->bounds());
-  host_impl().active_tree()->SetRootLayer(root.Pass());
-  host_impl().active_tree()->UpdateDrawProperties();
-
-  // Verify that the root layer and empty layers with touch/wheel handlers
-  // (but not the empty layer without a touch handler) are in the RSSL.
-  ASSERT_EQ(1u, RenderSurfaceLayerList().size());
-  EXPECT_EQ(1, RenderSurfaceLayerList()[0]->id());
-  ASSERT_EQ(3u, root_layer()->render_surface()->layer_list().size());
-  EXPECT_EQ(1, root_layer()->render_surface()->layer_list().at(0)->id());
-  EXPECT_EQ(3, root_layer()->render_surface()->layer_list().at(1)->id());
-  EXPECT_EQ(4, root_layer()->render_surface()->layer_list().at(2)->id());
-
-  // Hit testing for a point inside the empty no-handlers layer should return
-  // the root layer.
-  gfx::Point test_point = gfx::Point(15, 15);
-  LayerImpl* result_layer =
-      host_impl().active_tree()->FindLayerThatIsHitByPoint(test_point);
-  ASSERT_TRUE(result_layer);
-  EXPECT_EQ(1, result_layer->id());
-
-  // Hit testing for a point inside the touch handler layer should return it.
-  test_point = gfx::Point(15, 75);
-  result_layer =
-      host_impl().active_tree()->FindLayerThatIsHitByPoint(test_point);
-  ASSERT_TRUE(result_layer);
-  EXPECT_EQ(3, result_layer->id());
-
-  // Hit testing for a point inside the mousewheel layer should return it.
-  test_point = gfx::Point(75, 75);
-  result_layer =
-      host_impl().active_tree()->FindLayerThatIsHitByPoint(test_point);
-  ASSERT_TRUE(result_layer);
-  EXPECT_EQ(4, result_layer->id());
-}
-
 TEST_F(LayerTreeImplTest, HitCheckingTouchHandlerRegionsForSingleLayer) {
   scoped_ptr<LayerImpl> root =
       LayerImpl::Create(host_impl().active_tree(), 12345);
diff --git a/cc/trees/occlusion_tracker.cc b/cc/trees/occlusion_tracker.cc
index 94125be..ceb2d14 100644
--- a/cc/trees/occlusion_tracker.cc
+++ b/cc/trees/occlusion_tracker.cc
@@ -404,9 +404,6 @@ void OcclusionTracker<LayerType>::MarkOccludedBehindLayer(
   if (stack_.empty())
     return;
 
-  if (!layer->DrawsContent())
-    return;
-
   if (!LayerOpacityKnown(layer) || layer->draw_opacity() < 1)
     return;
 
diff --git a/cc/trees/occlusion_tracker_unittest.cc b/cc/trees/occlusion_tracker_unittest.cc
index 8f083f5..4687dab 100644
--- a/cc/trees/occlusion_tracker_unittest.cc
+++ b/cc/trees/occlusion_tracker_unittest.cc
@@ -328,14 +328,6 @@ template <typename Types> class OcclusionTrackerTest : public testing::Test {
         Types::TestLayerIterator::Begin(render_surface_layer_list_.get());
   }
 
-  void SetDrawsContent(LayerImpl* layer_impl, bool draws_content) {
-    layer_impl->SetDrawsContent(draws_content);
-  }
-
-  void SetDrawsContent(Layer* layer, bool draws_content) {
-    layer->SetIsDrawable(draws_content);
-  }
-
   void EnterLayer(typename Types::LayerType* layer,
                   typename Types::OcclusionTrackerType* occlusion) {
     ASSERT_EQ(layer, *layer_iterator_);
@@ -3565,36 +3557,5 @@ class OcclusionTrackerTestHiddenCopyRequestDoesNotOcclude
 
 ALL_OCCLUSIONTRACKER_TEST(OcclusionTrackerTestHiddenCopyRequestDoesNotOcclude)
 
-template <class Types>
-class OcclusionTrackerTestEmptyEventLayerDoesNotOcclude
-    : public OcclusionTrackerTest<Types> {
- protected:
-  explicit OcclusionTrackerTestEmptyEventLayerDoesNotOcclude(
-      bool opaque_layers)
-      : OcclusionTrackerTest<Types>(opaque_layers) {}
-  void RunMyTest() {
-    typename Types::ContentLayerType* root = this->CreateRoot(
-        this->identity_matrix, gfx::Point(), gfx::Size(400, 400));
-    typename Types::ContentLayerType* empty_layer = this->CreateDrawingLayer(
-        root, this->identity_matrix, gfx::Point(), gfx::Size(200, 200), true);
-    this->SetDrawsContent(empty_layer, false);
-    empty_layer->SetTouchEventHandlerRegion(gfx::Rect(10, 10, 10, 10));
-
-    this->CalcDrawEtc(root);
-
-    TestOcclusionTrackerWithClip<typename Types::LayerType> occlusion(
-        gfx::Rect(0, 0, 1000, 1000));
-
-    this->VisitLayer(empty_layer, &occlusion);
-
-    EXPECT_EQ(gfx::Rect().ToString(),
-              occlusion.occlusion_from_outside_target().ToString());
-    EXPECT_EQ(gfx::Rect().ToString(),
-              occlusion.occlusion_from_inside_target().ToString());
-  }
-};
-
-ALL_OCCLUSIONTRACKER_TEST(OcclusionTrackerTestEmptyEventLayerDoesNotOcclude)
-
 }  // namespace
 }  // namespace cc