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 5df8fc4ac529125338aad564e79f8ab93e7855aa..2d3a1bbd254b0f0a78f868cba83369c7092d61cf 100644
--- a/cc/trees/layer_tree_host.cc
+++ b/cc/trees/layer_tree_host.cc
@@ -28,6 +28,7 @@
 #include "cc/layers/layer_iterator.h"
 #include "cc/layers/painted_scrollbar_layer.h"
 #include "cc/layers/render_surface.h"
+#include "cc/output/selection_handle.h"
 #include "cc/resources/prioritized_resource_manager.h"
 #include "cc/resources/ui_resource_request.h"
 #include "cc/trees/layer_tree_host_client.h"
@@ -328,6 +329,12 @@ void LayerTreeHost::FinishCommitOnImplThread(LayerTreeHostImpl* host_impl) {
     sync_tree->ClearViewportLayers();
   }
 
+  sync_tree->RegisterSelection(
+      start_selection_layer_ ? start_selection_layer_->id() : 0,
+      start_selection_handle_,
+      end_selection_layer_ ? end_selection_layer_->id() : 0,
+      end_selection_handle_);
+
   float page_scale_delta, sent_page_scale_delta;
   if (settings_.impl_side_painting) {
     // Update the delta from the active tree, which may have
@@ -1246,6 +1253,23 @@ void LayerTreeHost::RegisterViewportLayers(
   outer_viewport_scroll_layer_ = outer_viewport_scroll_layer;
 }
 
+void LayerTreeHost::RegisterSelection(scoped_refptr<Layer> start_layer,
+                                      const SelectionHandle& start_handle,
+                                      scoped_refptr<Layer> end_layer,
+                                      const SelectionHandle& end_handle) {
+  if (start_selection_layer_.get() == start_layer.get() &&
+      end_selection_layer_.get() == end_layer.get() &&
+      start_selection_handle_ == start_handle &&
+      end_selection_handle_ == end_handle)
+    return;
+
+  start_selection_layer_ = start_layer;
+  end_selection_layer_ = end_layer;
+  start_selection_handle_ = start_handle;
+  end_selection_handle_ = end_handle;
+  SetNeedsCommit();
+}
+
 int LayerTreeHost::ScheduleMicroBenchmark(
     const std::string& benchmark_name,
     scoped_ptr<base::Value> value,