Add line height setting to views::Label & use it for notifications.

ui/views/controls/button/text_button.cc

Index: ui/views/controls/button/text_button.cc
diff --git a/ui/views/controls/button/text_button.cc b/ui/views/controls/button/text_button.cc
index dd4d1506a69566c09b65547a1def3f4a9d3c010c..5382703ea2ee27fd7b0d345896068bc1eac26b0b 100644
--- a/ui/views/controls/button/text_button.cc
+++ b/ui/views/controls/button/text_button.cc
@@ -376,7 +376,7 @@ void TextButtonBase::CalculateTextSize(gfx::Size* text_size, int max_width) {
   if (!multi_line_)
     flags |= gfx::Canvas::NO_ELLIPSIS;
 
-  gfx::Canvas::SizeStringInt(text_, font_, &w, &h, flags);
+  gfx::Canvas::SizeStringInt(text_, font_, &w, &h, -1, flags);
   text_size->SetSize(w, h);
 }
 
@@ -498,6 +498,7 @@ void TextButtonBase::PaintButton(gfx::Canvas* canvas, PaintButtonMode mode) {
         shadows.push_back(gfx::ShadowValue(text_shadow_offset_, 0, color));
       }
       canvas->DrawStringWithShadows(text_, font_, text_color, text_bounds,
+                                    -1,  // Default line height.
                                     draw_string_flags, shadows);
     }
   }