views: Mark single-argument constructors as explicit.

ui/views/controls/button/text_button.h

Index: ui/views/controls/button/text_button.h
diff --git a/ui/views/controls/button/text_button.h b/ui/views/controls/button/text_button.h
index 3d84dc0c6d3f1c034d9fded0625ff95d1bb25c1d..e4e218fcb9c9ebcdb8005fde90d5df7fb8a81938 100644
--- a/ui/views/controls/button/text_button.h
+++ b/ui/views/controls/button/text_button.h
@@ -92,7 +92,7 @@ class VIEWS_EXPORT TextButtonBorder : public Border {
 ////////////////////////////////////////////////////////////////////////////////
 class VIEWS_EXPORT TextButtonNativeThemeBorder : public Border {
  public:
-   TextButtonNativeThemeBorder(NativeThemeDelegate* delegate);
+  explicit TextButtonNativeThemeBorder(NativeThemeDelegate* delegate);
   virtual ~TextButtonNativeThemeBorder();
 
   // Implementation of Border:
@@ -399,12 +399,11 @@ class VIEWS_EXPORT NativeTextButton : public TextButton {
   // The button's class name.
   static const char kViewClassName[];
 
-  NativeTextButton(ButtonListener* listener);
+  explicit NativeTextButton(ButtonListener* listener);
   NativeTextButton(ButtonListener* listener, const string16& text);
 
   // Overridden from TextButton:
   virtual gfx::Size GetMinimumSize() OVERRIDE;
-
   virtual std::string GetClassName() const OVERRIDE;
 
  private: