Do not mark active LayerImpls as needing to push layer properties.

Active LayerImpl properties are never pushed. This patch enforces this
by making LayerImpl::SetNeedsPushProperties only work on the pending tree.

The existing VerifyLayerChangesAreTrackedProperly test has been modified
to work on the pending tree instead of the active tree. The existing
mask_to_bounds tests have been updated as they were intended for
another era when SetBounds did depend on mask_to_bounds.

An additional test has been added for active layer change tracking.

Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I711109df86e6c644333a8e14a5540a4b22675894
Reviewed-on: https://chromium-review.googlesource.com/516826
Commit-Queue: Philip Rogers <pdr@chromium.org>
Reviewed-by: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#475779}

cc/layers/layer_impl.cc

@@ -771,7 +771,8 @@ gfx::Vector2dF LayerImpl::ClampScrollToMaxScrollOffset() {
 }
 
 void LayerImpl::SetNeedsPushProperties() {
-  if (layer_tree_impl_ && !needs_push_properties_) {
+  // There's no need to push layer properties on the active tree.
+  if (!needs_push_properties_ && !layer_tree_impl()->IsActiveTree()) {
     needs_push_properties_ = true;
     layer_tree_impl()->AddLayerShouldPushProperties(this);
   }

cc/trees/layer_tree_impl.cc

@@ -1247,6 +1247,7 @@ void LayerTreeImpl::ClearSurfaceLayerIds() {
 }
 
 void LayerTreeImpl::AddLayerShouldPushProperties(LayerImpl* layer) {
+  DCHECK(!IsActiveTree()) << "The active tree does not push layer properties";
   layers_that_should_push_properties_.insert(layer);
 }