Aura tooltips do not move on mouse move in case of many neighboring views with the same label

ui/views/corewm/tooltip_controller.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/corewm/tooltip_controller.h"
 
 #include <vector>
 
 #include "base/strings/string_util.h"
 #include "base/time/time.h"
@@ skipping 97 matching lines @@
   return NULL;
 }
 
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
 // TooltipController public:
 
 TooltipController::TooltipController(scoped_ptr<Tooltip> tooltip)
     : tooltip_window_(NULL),
+      tooltip_id_(NULL),
       tooltip_window_at_mouse_press_(NULL),
       tooltip_(tooltip.Pass()),
       tooltips_enabled_(true) {
   tooltip_timer_.Start(FROM_HERE,
       base::TimeDelta::FromMilliseconds(kTooltipTimeoutMs),
       this, &TooltipController::TooltipTimerFired);
 }
 
 TooltipController::~TooltipController() {
   if (tooltip_window_)
@@ skipping 147 matching lines @@
   // it until there is a change in the tooltip.
   if (tooltip_window_at_mouse_press_) {
     if (tooltip_window_ == tooltip_window_at_mouse_press_ &&
         tooltip_text == tooltip_text_at_mouse_press_) {
       tooltip_->Hide();
       return;
     }
     tooltip_window_at_mouse_press_ = NULL;
   }
 
+  // If the uniqueness indicator is different from the previously encountered
+  // one, we should force tooltip update
+  const void* tooltip_id = aura::client::GetTooltipId(tooltip_window_);
+  bool ids_differ = false;
+  if (tooltip_id) {

[sky, 2014/06/02 15:39:47]

Why the if here? Can't you always compare tooltip_id_ and tooltip_id?

+    ids_differ = tooltip_id_ != tooltip_id;
+    tooltip_id_ = tooltip_id;
+  } else {
+    tooltip_id_ = NULL;
+  }
+
   // We add the !tooltip_->IsVisible() below because when we come here from
   // TooltipTimerFired(), the tooltip_text may not have changed but we still
   // want to update the tooltip because the timer has fired.
   // If we come here from UpdateTooltip(), we have already checked for tooltip
   // visibility and this check below will have no effect.
-  if (tooltip_text_ != tooltip_text || !tooltip_->IsVisible()) {
+  if (tooltip_text_ != tooltip_text || !tooltip_->IsVisible() || ids_differ) {
     tooltip_shown_timer_.Stop();
     tooltip_text_ = tooltip_text;
     base::string16 trimmed_text(tooltip_text_);
     views::TooltipManager::TrimTooltipText(&trimmed_text);
     // If the string consists entirely of whitespace, then don't both showing it
     // (an empty tooltip is useless).
     base::string16 whitespace_removed_text;
     base::TrimWhitespace(trimmed_text, base::TRIM_ALL,
                          &whitespace_removed_text);
     if (whitespace_removed_text.empty()) {
@@ skipping 50 matching lines @@
     return;
   if (tooltip_window_)
     tooltip_window_->RemoveObserver(this);
   tooltip_window_ = target;
   if (tooltip_window_)
     tooltip_window_->AddObserver(this);
 }
 
 }  // namespace corewm
 }  // namespace views