Revert of Splitting of layers for correct intersections

cc/trees/occlusion_tracker_unittest.cc

Index: cc/trees/occlusion_tracker_unittest.cc
diff --git a/cc/trees/occlusion_tracker_unittest.cc b/cc/trees/occlusion_tracker_unittest.cc
index f3f218570eb52a71f989222dc88afc1ca3c53371..e3639adeb0a99f04a9022e459b09fd3aedda8204 100644
--- a/cc/trees/occlusion_tracker_unittest.cc
+++ b/cc/trees/occlusion_tracker_unittest.cc
@@ -1539,6 +1539,56 @@
     EXPECT_TRUE(occlusion.occlusion_from_outside_target().IsEmpty());
   }
 };
+
+// This test requires accumulating occlusion of 3d layers, which are skipped by
+// the occlusion tracker on the main thread. So this test should run on the impl
+// thread.
+IMPL_THREAD_TEST(OcclusionTrackerTestLayerBehindCameraDoesNotOcclude);
+
+template <class Types>
+class OcclusionTrackerTestLargePixelsOccludeInsideClipRect
+    : public OcclusionTrackerTest<Types> {
+ protected:
+  explicit OcclusionTrackerTestLargePixelsOccludeInsideClipRect(
+      bool opaque_layers)
+      : OcclusionTrackerTest<Types>(opaque_layers) {}
+  void RunMyTest() override {
+    gfx::Transform transform;
+    transform.Translate(50.0, 50.0);
+    transform.ApplyPerspectiveDepth(100.0);
+    transform.Translate3d(0.0, 0.0, 99.0);
+    transform.Translate(-50.0, -50.0);
+
+    typename Types::ContentLayerType* parent = this->CreateRoot(
+        this->identity_matrix, gfx::PointF(), gfx::Size(100, 100));
+    parent->SetMasksToBounds(true);
+    typename Types::ContentLayerType* layer = this->CreateDrawingLayer(
+        parent, transform, gfx::PointF(), gfx::Size(100, 100), true);
+    parent->SetShouldFlattenTransform(false);
+    parent->Set3dSortingContextId(1);
+    layer->SetShouldFlattenTransform(false);
+    layer->Set3dSortingContextId(1);
+    this->CalcDrawEtc(parent);
+
+    TestOcclusionTrackerWithClip<typename Types::LayerType> occlusion(
+        gfx::Rect(0, 0, 1000, 1000));
+
+    // This is very close to the camera, so pixels in its visible_content_rect()
+    // will actually go outside of the layer's clip rect.  Ensure that those
+    // pixels don't occlude things outside the clip rect.
+    this->VisitLayer(layer, &occlusion);
+    this->EnterLayer(parent, &occlusion);
+    EXPECT_EQ(gfx::Rect(0, 0, 100, 100).ToString(),
+              occlusion.occlusion_from_inside_target().ToString());
+    EXPECT_EQ(gfx::Rect().ToString(),
+              occlusion.occlusion_from_outside_target().ToString());
+  }
+};
+
+// This test requires accumulating occlusion of 3d layers, which are skipped by
+// the occlusion tracker on the main thread. So this test should run on the impl
+// thread.
+IMPL_THREAD_TEST(OcclusionTrackerTestLargePixelsOccludeInsideClipRect);
 
 template <class Types>
 class OcclusionTrackerTestAnimationOpacity1OnMainThread