cc: Always call PrepareTiles on visibility change.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index 6dc9043559c3df4eeb2c286e7b6baf4f1f2dbecf..0d4d5a0235c0481802a6b36db94786fd3bfaa846 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -1948,10 +1948,11 @@ void LayerTreeHostImpl::SetVisible(bool visible) {
   else
     EvictAllUIResources();
 
-  // Evict tiles immediately if invisible since this tab may never get another
-  // draw or timer tick.
-  if (!visible_)
-    PrepareTiles();
+  // Call PrepareTiles unconditionally on visibility change since this tab may
+  // never get another draw or timer tick. When becoming visible we care about
+  // unblocking the scheduler which might be waiting for activation / ready to
+  // draw. When becoming invisible we care about evicting tiles immediately.
+  PrepareTiles();
 
   if (!renderer_)
     return;