Add GetMinimumSize() for Labels and ensure it's zero for empty Links.

ui/views/controls/label.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/controls/label.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <vector>
 
 #include "base/i18n/rtl.h"
 #include "base/logging.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/base/accessibility/accessible_view_state.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/color_utils.h"
 #include "ui/gfx/insets.h"
 #include "ui/gfx/shadow_value.h"
 #include "ui/gfx/text_elider.h"
 #include "ui/gfx/text_utils.h"
 #include "ui/native_theme/native_theme.h"
 #include "ui/views/background.h"
 
 namespace {
 
-// The padding for the focus border when rendering focused text.
-const int kFocusBorderPadding = 1;
 const int kCachedSizeLimit = 10;
 
 gfx::FontList GetDefaultFontList() {
   return ui::ResourceBundle::GetSharedInstance().GetFontList(
       ui::ResourceBundle::BaseFont);
 }
 
 }  // namespace
 
 namespace views {
 
 // static
 const char Label::kViewClassName[] = "Label";
+const int Label::kFocusBorderPadding = 1;
 
 Label::Label() {
   Init(string16(), GetDefaultFontList());
 }
 
 Label::Label(const string16& text) {
   Init(text, GetDefaultFontList());
 }
 
 Label::Label(const string16& text, const gfx::FontList& font_list) {
@@ skipping 139 matching lines @@
 
   label_width += GetInsets().width();
 
   if (max_width > 0)
     label_width = std::min(label_width, max_width);
 
   SetBounds(x(), y(), label_width, 0);
   SizeToPreferredSize();
 }
 
-void Label::SetHasFocusBorder(bool has_focus_border) {
-  has_focus_border_ = has_focus_border;
-  if (is_multi_line_) {
-    ResetCachedSize();
-    PreferredSizeChanged();
-  }
-}
-
 gfx::Insets Label::GetInsets() const {
   gfx::Insets insets = View::GetInsets();
-  if (focusable() || has_focus_border_) {
+  if (IsFocusable()) {

[sky, 2013/12/10 17:18:00]

Why do you want IsFocusable() here rather than focusable_? One potential bad
thing about IsFocusable() is that it uses IsDrawn, which means the return value
changes once added to a Widget. I tend to think you only care about focusable_
here.

     insets += gfx::Insets(kFocusBorderPadding, kFocusBorderPadding,
                           kFocusBorderPadding, kFocusBorderPadding);
   }
   return insets;
 }
 
 int Label::GetBaseline() const {
   return GetInsets().top() + font_list_.GetBaseline();
 }
 
 gfx::Size Label::GetPreferredSize() {
   // Return a size of (0, 0) if the label is not visible and if the
   // collapse_when_hidden_ flag is set.
   // TODO(munjal): This logic probably belongs to the View class. But for now,
   // put it here since putting it in View class means all inheriting classes
   // need ot respect the collapse_when_hidden_ flag.
   if (!visible() && collapse_when_hidden_)
     return gfx::Size();
 
-  gfx::Size prefsize(GetTextSize());
+  gfx::Size size(GetTextSize());
   gfx::Insets insets = GetInsets();
-  prefsize.Enlarge(insets.width(), insets.height());
-  return prefsize;
+  size.Enlarge(insets.width(), insets.height());
+  return size;
+}
+
+gfx::Size Label::GetMinimumSize() {
+  gfx::Size text_size(GetTextSize());
+  if ((!visible() && collapse_when_hidden_) || text_size.IsEmpty())
+    return gfx::Size();
+
+  gfx::Size size(font_list_.GetStringWidth(string16(gfx::kEllipsisUTF16)),
+                 font_list_.GetHeight());
+  size.SetToMin(text_size);  // The actual text may be shorter than an ellipsis.
+  gfx::Insets insets = GetInsets();
+  size.Enlarge(insets.width(), insets.height());
+  return size;
 }
 
 int Label::GetHeightForWidth(int w) {
   if (!is_multi_line_)
     return View::GetHeightForWidth(w);
 
   w = std::max(0, w - GetInsets().width());
 
   for (size_t i = 0; i < cached_heights_.size(); ++i) {
     const gfx::Size& s = cached_heights_[i];
@@ skipping 126 matching lines @@
   enabled_color_set_ = disabled_color_set_ = background_color_set_ = false;
   auto_color_readability_ = true;
   UpdateColorsFromTheme(ui::NativeTheme::instance());
   horizontal_alignment_ = gfx::ALIGN_CENTER;
   line_height_ = 0;
   is_multi_line_ = false;
   allow_character_break_ = false;
   elide_behavior_ = ELIDE_AT_END;
   collapse_when_hidden_ = false;
   directionality_mode_ = USE_UI_DIRECTIONALITY;
-  has_focus_border_ = false;
   enabled_shadow_color_ = 0;
   disabled_shadow_color_ = 0;
   shadow_offset_.SetPoint(1, 1);
   has_shadow_ = false;
   cached_heights_.resize(kCachedSizeLimit);
   ResetCachedSize();
 
   SetText(text);
 }
 
@@ skipping 139 matching lines @@
   for (int i = 0; i < kCachedSizeLimit; ++i)
     cached_heights_[i] = gfx::Size();
 }
 
 bool Label::ShouldShowDefaultTooltip() const {
   return !is_multi_line_ &&
       gfx::GetStringWidth(text_, font_list_) > GetAvailableRect().width();
 }
 
 }  // namespace views