Fix regression: empty tooltip appears in Linux and Chrome OS

ui/views/corewm/tooltip_controller.cc

Index: ui/views/corewm/tooltip_controller.cc
diff --git a/ui/views/corewm/tooltip_controller.cc b/ui/views/corewm/tooltip_controller.cc
index a52c806a9928e56dd9a4f212c9535e1e456da06d..197bd07e3f50770dd29fd08dbe23aafd5af68a16 100644
--- a/ui/views/corewm/tooltip_controller.cc
+++ b/ui/views/corewm/tooltip_controller.cc
@@ -308,6 +308,9 @@ void TooltipController::UpdateIfRequired() {
                          &tooltip_text_whitespace_trimmed_);
     if (tooltip_text_whitespace_trimmed_.empty()) {
       tooltip_->Hide();
+      if (tooltip_defer_timer_.IsRunning()) {

[sky, 2017/01/26 18:25:37]

no {}

[chengx, 2017/01/26 21:04:03]

Done.

+        tooltip_defer_timer_.Reset();
+      }
     } else if (tooltip_show_delayed_) {
       // Initialize the one-shot timer to show the tooltip in a while.
       // If there is already a request queued then cancel it and post the new
@@ -327,7 +330,7 @@ void TooltipController::UpdateIfRequired() {
 }
 
 void TooltipController::ShowTooltip() {
-  if (!tooltip_window_)
+  if (!tooltip_window_ || tooltip_text_whitespace_trimmed_.empty())
     return;
   gfx::Point widget_loc =
       curr_mouse_loc_ + tooltip_window_->GetBoundsInScreen().OffsetFromOrigin();