Route selection bounds updates through the compositor

cc/trees/layer_tree_host.cc

Index: cc/trees/layer_tree_host.cc
diff --git a/cc/trees/layer_tree_host.cc b/cc/trees/layer_tree_host.cc
index fe77820fedc7c7d9444521efbb7761b2dd77e780..bbfd51e7247adb0a25ba9af7a33764606b0ec73d 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -21,6 +21,7 @@
 #include "cc/base/math_util.h"
 #include "cc/debug/devtools_instrumentation.h"
 #include "cc/debug/rendering_stats_instrumentation.h"
+#include "cc/input/layer_selection_bound.h"
 #include "cc/input/top_controls_manager.h"
 #include "cc/layers/heads_up_display_layer.h"
 #include "cc/layers/heads_up_display_layer_impl.h"
@@ -328,6 +329,8 @@ void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
     sync_tree->ClearViewportLayers();
   }
 
+  sync_tree->RegisterSelection(selection_anchor_, selection_focus_);
+
   float page_scale_delta, sent_page_scale_delta;
   if (settings_.impl_side_painting) {
     // Update the delta from the active tree, which may have
@@ -1257,6 +1260,16 @@ void LayerTreeHost::RegisterViewportLayers(
   outer_viewport_scroll_layer_ = outer_viewport_scroll_layer;
 }
 
+void LayerTreeHost::RegisterSelection(const LayerSelectionBound& anchor,
+                                      const LayerSelectionBound& focus) {
+  if (selection_anchor_ == anchor && selection_focus_ == focus)
+    return;
+
+  selection_anchor_ = anchor;
+  selection_focus_ = focus;
+  SetNeedsCommit();
+}
+
 int LayerTreeHost::ScheduleMicroBenchmark(
     const std::string& benchmark_name,
     scoped_ptr<base::Value> value,