[Smart Lock] Add a private API to show an error bubble anchored to the Smart Lock app window.

ui/views/controls/styled_label.h

Index: ui/views/controls/styled_label.h
diff --git a/ui/views/controls/styled_label.h b/ui/views/controls/styled_label.h
index adbd7a99ba27cdab3d83074ecdb1dc57b8765faf..0be1d9907caca524867c2e195c311227f8a7e353 100644
--- a/ui/views/controls/styled_label.h
+++ b/ui/views/controls/styled_label.h
@@ -90,8 +90,17 @@ class VIEWS_EXPORT StyledLabel : public View, public LinkListener {
     auto_color_readability_enabled_ = auto_color_readability;
   }
 
+  // Resizes the label so its width is set to the width of the longest line and
+  // its height deduced accordingly.
+  // This is only intended for multi-line labels and is useful when the label's
+  // text contains several lines separated with \n.
+  // |max_width| is the maximum width that will be used (longer lines will be
+  // wrapped). If 0, no maximum width is enforced.
+  void SizeToFit(int max_width);

[sky, 2015/01/20 16:24:36]

Isn't this the same as:

SetSize(gfx::Size(max_width, GetHeightForWidth(max_width)) ?

[Ilya Sherman, 2015/01/22 02:26:27]

Not quite.  SizeToFit will never size to a width greater than max_width, but it
will typically size to a smaller width -- whatever width is needed to fit the
text.  The result is that there isn't a bunch of awkward whitespace on the right
side of the bubble, where text could theoretically be drawn, but doesn't fit due
to word wrapping.

Note that I chose this name and max_width conventions to match the Label
implementation.

+
   // View implementation:
   gfx::Insets GetInsets() const override;
+  gfx::Size GetPreferredSize() const override;
   int GetHeightForWidth(int w) const override;
   void Layout() override;
   void PreferredSizeChanged() override;
@@ -115,10 +124,11 @@ class VIEWS_EXPORT StyledLabel : public View, public LinkListener {
   };
   typedef std::list<StyleRange> StyleRanges;
 
-  // Calculates how to layout child views, creates them and sets their size
-  // and position. |width| is the horizontal space, in pixels, that the view
-  // has to work with. If |dry_run| is true, the view hierarchy is not touched.
-  // The return value is the necessary size.
+  // Calculates how to layout child views, creates them and sets their size and
+  // position. |width| is the horizontal space, in pixels, that the view has to
+  // work with. If |dry_run| is true, the view hierarchy is not touched. Caches
+  // the results in |calculated_size_|, |width_at_last_layout_|, and
+  // |width_at_last_size_calculation_|. Returns the needed size.
   gfx::Size CalculateAndDoLayout(int width, bool dry_run);
 
   // The text to display.
@@ -147,6 +157,7 @@ class VIEWS_EXPORT StyledLabel : public View, public LinkListener {
   // This variable saves the result of the last GetHeightForWidth call in order
   // to avoid repeated calculation.
   mutable gfx::Size calculated_size_;
+  mutable int width_at_last_size_calculation_;
   int width_at_last_layout_;
 
   // Background color on which the label is drawn, for auto color readability.