views: Mark single-argument constructors as explicit.

ui/views/widget/widget_unittest.cc

Index: ui/views/widget/widget_unittest.cc
diff --git a/ui/views/widget/widget_unittest.cc b/ui/views/widget/widget_unittest.cc
index b0d0c3b8d596b3af7fcbf9f65e07890df6226c69..df2c1b7fd0ff371be4ce4ffafa95cd089b92250c 100644
--- a/ui/views/widget/widget_unittest.cc
+++ b/ui/views/widget/widget_unittest.cc
@@ -36,7 +36,7 @@ typedef NativeWidgetWin NativeWidgetPlatform;
 #if defined(USE_AURA)
 class NativeWidgetCapture : public NativeWidgetPlatform {
  public:
-  NativeWidgetCapture(internal::NativeWidgetDelegate* delegate)
+  explicit NativeWidgetCapture(internal::NativeWidgetDelegate* delegate)
       : NativeWidgetPlatform(delegate),
         mouse_capture_(false) {}
   virtual ~NativeWidgetCapture() {}
@@ -404,7 +404,7 @@ class OwnershipTestNativeWidgetPlatform : public NativeWidgetPlatformForTest {
 // A Widget subclass that updates a bag of state when it is destroyed.
 class OwnershipTestWidget : public Widget {
  public:
-  OwnershipTestWidget(OwnershipTestState* state) : state_(state) {}
+  explicit OwnershipTestWidget(OwnershipTestState* state) : state_(state) {}
   virtual ~OwnershipTestWidget() {
     state_->widget_deleted = true;
   }