Fix compositor_unittests failures in UBSanVptr Linux builder

It turns out layer_tree_host_ can be nullptr in tests which
passes unexpectedly on bots other than UBSan bots. This CL
fixes this behavior.

Bug: 989936
Test: compositor_unittests on the UBsan gn flags
Change-Id: I6e8ff606709b07f19e6309e3b5a96ca240f0de99
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1731954Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Jun Mukai <mukai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683419}

cc/layers/layer.cc

@@ -664,9 +664,10 @@ void Layer::SetRoundedCorner(const gfx::RoundedCornersF& corner_radii) {
   inputs_.corner_radii = corner_radii;
   SetSubtreePropertyChanged();
   SetNeedsCommit();
-  PropertyTrees* property_trees = layer_tree_host_->property_trees();
+  PropertyTrees* property_trees =
+      layer_tree_host_ ? layer_tree_host_->property_trees() : nullptr;
   EffectNode* node = nullptr;
-  if (effect_tree_index() != EffectTree::kInvalidNodeId &&
+  if (property_trees && effect_tree_index() != EffectTree::kInvalidNodeId &&
       (node = property_trees->effect_tree.Node(effect_tree_index()))) {
     node->rounded_corner_bounds =
         gfx::RRectF(EffectiveClipRect(), corner_radii);

ui/compositor/layer_unittest.cc

@@ -774,13 +774,7 @@ TEST_P(LayerWithRealCompositorTest, HierarchyNoTexture) {
   EXPECT_TRUE(d3.painted());
 }
 
-// crbug.com/989936
-#if defined(OS_LINUX) && defined(UNDEFINED_SANITIZER)
-#define MAYBE_Cloning DISABLED_Cloning
-#else
-#define MAYBE_Cloning Cloning
-#endif
-TEST_F(LayerWithDelegateTest, MAYBE_Cloning) {
+TEST_F(LayerWithDelegateTest, Cloning) {
   std::unique_ptr<Layer> layer = CreateLayer(LAYER_SOLID_COLOR);
 
   gfx::Transform transform;
@@ -1045,14 +1039,8 @@ TEST_F(LayerWithNullDelegateTest, EscapedDebugNames) {
   ASSERT_TRUE(roundtrip);
   EXPECT_EQ(name, *roundtrip);
 }
-// crbug.com/989936
-#if defined(OS_LINUX) && defined(UNDEFINED_SANITIZER)
-#define MAYBE_SwitchLayerPreservesCCLayerState \
-  DISABLED_SwitchLayerPreservesCCLayerState
-#else
-#define MAYBE_SwitchLayerPreservesCCLayerState SwitchLayerPreservesCCLayerState
-#endif
-TEST_F(LayerWithNullDelegateTest, MAYBE_SwitchLayerPreservesCCLayerState) {
+
+TEST_F(LayerWithNullDelegateTest, SwitchLayerPreservesCCLayerState) {
   std::unique_ptr<Layer> l1 = CreateLayer(LAYER_SOLID_COLOR);
   l1->SetFillsBoundsOpaquely(true);
   l1->SetVisible(false);