[Mac] Don't show tooltip when zoom decoration is hidden.

chrome/browser/ui/cocoa/location_bar/zoom_decoration.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/location_bar/zoom_decoration.h"
 
 #include "base/i18n/number_formatting.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
@@ skipping 86 matching lines @@
   zoom::ZoomController::RelativeZoom relative_zoom =
       zoom_controller->GetZoomRelativeToDefault();
   if (relative_zoom == zoom::ZoomController::ZOOM_BELOW_DEFAULT_ZOOM) {
     vector_icon_id_ = gfx::VectorIconId::ZOOM_MINUS;
   } else if (relative_zoom == zoom::ZoomController::ZOOM_ABOVE_DEFAULT_ZOOM) {
     vector_icon_id_ = gfx::VectorIconId::ZOOM_PLUS;
   }
 
   SetImage(GetMaterialIcon(location_bar_is_dark));
 
-  tooltip_.reset([tooltip_string retain]);
+  tooltip_.reset(vector_icon_id_ == gfx::VectorIconId::VECTOR_ICON_NONE

[Avi (use Gerrit), 2016/10/12 19:40:10]

It's equivalent, but it feels better to do:

tooltip_.reset(relative_zoom == zoom::ZoomController::ZOOM_AT_DEFAULT_ZOOM
 ? @""
 : [tooltip_string retain]);

where we're gating on the zoom controller's response rather than an id
interpretation of it.

[shrike, 2016/10/12 20:43:36]

I like checking the icon id because it's explicit that no vector icon means no
tool tip either, but I'm fine to change it.

+                     ? @""
+                     : [tooltip_string retain]);
 
   SetVisible(true);
   [bubble_ onZoomChanged];
 }
 
 NSPoint ZoomDecoration::GetBubblePointInFrame(NSRect frame) {
   return NSMakePoint(NSMaxX(frame), NSMaxY(frame));
 }
 
 bool ZoomDecoration::IsAtDefaultZoom() const {
@@ skipping 41 matching lines @@
   // closed the decoration can be hidden.
   if (IsAtDefaultZoom() && IsVisible()) {
     SetVisible(false);
     owner_->OnDecorationsChanged();
   }
 }
 
 gfx::VectorIconId ZoomDecoration::GetMaterialVectorIconId() const {
   return vector_icon_id_;
 }