Fix candidate window position issue.

ui/base/ime/input_method_ibus.cc

Index: ui/base/ime/input_method_ibus.cc
diff --git a/ui/base/ime/input_method_ibus.cc b/ui/base/ime/input_method_ibus.cc
index d9a35cbb629c76f7ab88d1edd5df083f75f54943..89ac5aa500b1187450a06c2544688c7cc2f22f3f 100644
--- a/ui/base/ime/input_method_ibus.cc
+++ b/ui/base/ime/input_method_ibus.cc
@@ -334,9 +334,14 @@ void InputMethodIBus::OnCaretBoundsChanged(const TextInputClient* client) {
   DCHECK(!IsTextInputTypeNone());
   const gfx::Rect rect = GetTextInputClient()->GetCaretBounds();
 
+  gfx::Rect composition_head;
+  if (!GetTextInputClient()->GetCompositionCharacterBounds(0,
+                                                           &composition_head)) {
+    composition_head = gfx::Rect();
+  }
+
   // This function runs asynchronously.
-  ibus_client_->SetCursorLocation(
-      context_, rect.x(), rect.y(), rect.width(), rect.height());
+  ibus_client_->SetCursorLocation(context_, rect, composition_head);
 }
 
 void InputMethodIBus::CancelComposition(const TextInputClient* client) {