[refactor] Cleanup IME State in RenderWidgetHostViewMac which is already tracked by TextInputManager

content/browser/renderer_host/render_widget_host_view_base.cc

Index: content/browser/renderer_host/render_widget_host_view_base.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_base.cc b/content/browser/renderer_host/render_widget_host_view_base.cc
index d09da0790d0df887ac8265565c89e265dfe90e46..0f66b35dd6bc5d471029efaef0b4ec80b76564d3 100644
--- a/content/browser/renderer_host/render_widget_host_view_base.cc
+++ b/content/browser/renderer_host/render_widget_host_view_base.cc
@@ -168,15 +168,7 @@ void RenderWidgetHostViewBase::SetShowingContextMenu(bool showing) {
 base::string16 RenderWidgetHostViewBase::GetSelectedText() {
   if (!GetTextInputManager())
     return base::string16();
-
-  const TextInputManager::TextSelection* selection =
-      GetTextInputManager()->GetTextSelection(this);
-
-  if (!selection || !selection->range.IsValid())
-    return base::string16();
-
-  return selection->text.substr(selection->range.GetMin() - selection->offset,
-                                selection->range.length());
+  return GetTextInputManager()->GetTextSelection(this)->selected_text();
 }
 
 bool RenderWidgetHostViewBase::IsMouseLocked() {