cc: Fix size_t to int truncations in tiles/ and trees/

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index e6d9700043053afc091ed205e80e11e5d5eb047d..0564484597ab0dfccffa3188a64c2fe6b6a98e30 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -78,7 +78,7 @@ LayerImpl::LayerImpl(LayerTreeImpl* tree_impl,
       clip_tree_index_(-1),
       draw_depth_(0.f),
       needs_push_properties_(false),
-      num_dependents_need_push_properties_(0),
+      num_dependents_need_push_properties_(0u),
       sorting_context_id_(0),
       current_draw_mode_(DRAW_MODE_NONE),
       frame_timing_requests_dirty_(false),
@@ -1480,8 +1480,6 @@ void LayerImpl::SetNeedsPushProperties() {
 }
 
 void LayerImpl::AddDependentNeedsPushProperties() {
-  DCHECK_GE(num_dependents_need_push_properties_, 0);
-
   if (!parent_should_know_need_push_properties() && parent_)
     parent_->AddDependentNeedsPushProperties();
 
@@ -1489,8 +1487,8 @@ void LayerImpl::AddDependentNeedsPushProperties() {
 }
 
 void LayerImpl::RemoveDependentNeedsPushProperties() {
+  DCHECK_GT(num_dependents_need_push_properties_, 0u);
   num_dependents_need_push_properties_--;
-  DCHECK_GE(num_dependents_need_push_properties_, 0);
 
   if (!parent_should_know_need_push_properties() && parent_)
       parent_->RemoveDependentNeedsPushProperties();