Add a hide_layer_and_subtree() flag to cc::Layer

This flag does what it says. We can use this flag to simplify ui::Layer
as it was recursively calling SetIsDrawable() instead, and now can just
SetHideLayerAndSubtree() on a single layer.

This flag is needed to allow readbacks of layers that are have hidden
visibility (possibly due to an ancestor).

Tests:
LayerTest.CheckPropertyChangeCausesCorrectBehavior
LayerImplTest.VerifyLayerChangesAreTrackedProperly
LayerTreeHostCommonTest.SubtreeHidden_SingleLayer
LayerTreeHostCommonTest.SubtreeHidden_SingleLayerImpl
LayerTreeHostCommonTest.SubtreeHidden_TwoLayers
LayerTreeHostCommonTest.SubtreeHidden_TwoLayersImpl

R=enne, piman
BUG=242572

Review URL: https://chromiumcodereview.appspot.com/16896017

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207508 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 19 insertions, 36 deletions

diff --git a/ui/compositor/layer.cc b/ui/compositor/layer.cc
index 09009ea..f729c9e 100644
--- a/ui/compositor/layer.cc
+++ b/ui/compositor/layer.cc
@@ -47,7 +47,6 @@ Layer::Layer()
       compositor_(NULL),
       parent_(NULL),
       visible_(true),
-      is_drawn_(true),
       force_render_surface_(false),
       fills_bounds_opaquely_(true),
       layer_updated_externally_(false),
@@ -72,7 +71,6 @@ Layer::Layer(LayerType type)
       compositor_(NULL),
       parent_(NULL),
       visible_(true),
-      is_drawn_(true),
       force_render_surface_(false),
       fills_bounds_opaquely_(true),
       layer_updated_externally_(false),
@@ -142,7 +140,6 @@ void Layer::Add(Layer* child) {
   children_.push_back(child);
   cc_layer_->AddChild(child->cc_layer_);
   child->OnDeviceScaleFactorChanged(device_scale_factor_);
-  child->UpdateIsDrawn();
   if (GetCompositor())
     child->SendPendingThreadedAnimations();
 }
@@ -370,21 +367,10 @@ bool Layer::GetTargetVisibility() const {
 }
 
 bool Layer::IsDrawn() const {
-  return is_drawn_;
-}
-
-void Layer::UpdateIsDrawn() {
-  bool updated_is_drawn = visible_ && (!parent_ || parent_->IsDrawn());
-
-  if (updated_is_drawn == is_drawn_)
-    return;
-
-  is_drawn_ = updated_is_drawn;
-  cc_layer_->SetIsDrawable(is_drawn_ && type_ != LAYER_NOT_DRAWN);
-
-  for (size_t i = 0; i < children_.size(); ++i) {
-    children_[i]->UpdateIsDrawn();
-  }
+  const Layer* layer = this;
+  while (layer && layer->visible_)
+    layer = layer->parent_;
+  return layer == NULL;
 }
 
 bool Layer::ShouldDraw() const {
@@ -478,7 +464,7 @@ void Layer::SwitchToLayer(scoped_refptr<cc::Layer> new_layer) {
   cc_layer_->SetAnchorPoint(gfx::PointF());
   cc_layer_->SetContentsOpaque(fills_bounds_opaquely_);
   cc_layer_->SetForceRenderSurface(force_render_surface_);
-  cc_layer_->SetIsDrawable(IsDrawn());
+  cc_layer_->SetHideLayerAndSubtree(!visible_);
 }
 
 void Layer::SwitchCCLayerForTest() {
@@ -751,7 +737,7 @@ void Layer::SetBoundsImmediately(const gfx::Rect& bounds) {
   if (was_move) {
     // Don't schedule a draw if we're invisible. We'll schedule one
     // automatically when we get visible.
-    if (IsDrawn())
+    if (visible_)
       ScheduleDraw();
   } else {
     // Always schedule a paint, even if we're invisible.
@@ -773,7 +759,7 @@ void Layer::SetVisibilityImmediately(bool visible) {
     return;
 
   visible_ = visible;
-  UpdateIsDrawn();
+  cc_layer_->SetHideLayerAndSubtree(!visible_);
 }
 
 void Layer::SetBrightnessImmediately(float brightness) {
diff --git a/ui/compositor/layer.h b/ui/compositor/layer.h
index 1159d0b..d536bf8 100644
--- a/ui/compositor/layer.h
+++ b/ui/compositor/layer.h
@@ -409,9 +409,6 @@ class COMPOSITOR_EXPORT Layer
   // Visibility of this layer. See SetVisible/IsDrawn for more details.
   bool visible_;
 
-  // Computed based on the visibility of this layer and its ancestors.
-  bool is_drawn_;
-
   bool force_render_surface_;
 
   bool fills_bounds_opaquely_;
diff --git a/ui/compositor/layer_unittest.cc b/ui/compositor/layer_unittest.cc
index c326d4a..0be8a0a 100644
--- a/ui/compositor/layer_unittest.cc
+++ b/ui/compositor/layer_unittest.cc
@@ -646,9 +646,9 @@ TEST_F(LayerWithNullDelegateTest, Visibility) {
   EXPECT_TRUE(l1->IsDrawn());
   EXPECT_TRUE(l2->IsDrawn());
   EXPECT_TRUE(l3->IsDrawn());
-  EXPECT_TRUE(l1->cc_layer()->DrawsContent());
-  EXPECT_TRUE(l2->cc_layer()->DrawsContent());
-  EXPECT_TRUE(l3->cc_layer()->DrawsContent());
+  EXPECT_FALSE(l1->cc_layer()->hide_layer_and_subtree());
+  EXPECT_FALSE(l2->cc_layer()->hide_layer_and_subtree());
+  EXPECT_FALSE(l3->cc_layer()->hide_layer_and_subtree());
 
   compositor()->SetRootLayer(l1.get());
 
@@ -658,25 +658,25 @@ TEST_F(LayerWithNullDelegateTest, Visibility) {
   EXPECT_FALSE(l1->IsDrawn());
   EXPECT_FALSE(l2->IsDrawn());
   EXPECT_FALSE(l3->IsDrawn());
-  EXPECT_FALSE(l1->cc_layer()->DrawsContent());
-  EXPECT_FALSE(l2->cc_layer()->DrawsContent());
-  EXPECT_FALSE(l3->cc_layer()->DrawsContent());
+  EXPECT_TRUE(l1->cc_layer()->hide_layer_and_subtree());
+  EXPECT_FALSE(l2->cc_layer()->hide_layer_and_subtree());
+  EXPECT_FALSE(l3->cc_layer()->hide_layer_and_subtree());
 
   l3->SetVisible(false);
   EXPECT_FALSE(l1->IsDrawn());
   EXPECT_FALSE(l2->IsDrawn());
   EXPECT_FALSE(l3->IsDrawn());
-  EXPECT_FALSE(l1->cc_layer()->DrawsContent());
-  EXPECT_FALSE(l2->cc_layer()->DrawsContent());
-  EXPECT_FALSE(l3->cc_layer()->DrawsContent());
+  EXPECT_TRUE(l1->cc_layer()->hide_layer_and_subtree());
+  EXPECT_FALSE(l2->cc_layer()->hide_layer_and_subtree());
+  EXPECT_TRUE(l3->cc_layer()->hide_layer_and_subtree());
 
   l1->SetVisible(true);
   EXPECT_TRUE(l1->IsDrawn());
   EXPECT_TRUE(l2->IsDrawn());
   EXPECT_FALSE(l3->IsDrawn());
-  EXPECT_TRUE(l1->cc_layer()->DrawsContent());
-  EXPECT_TRUE(l2->cc_layer()->DrawsContent());
-  EXPECT_FALSE(l3->cc_layer()->DrawsContent());
+  EXPECT_FALSE(l1->cc_layer()->hide_layer_and_subtree());
+  EXPECT_FALSE(l2->cc_layer()->hide_layer_and_subtree());
+  EXPECT_TRUE(l3->cc_layer()->hide_layer_and_subtree());
 }
 
 // Checks that stacking-related methods behave as advertised.