Add missing (and remove superfluous) 'explicit' from constructors.

ui/gfx/image/image_skia_unittest.cc

Index: ui/gfx/image/image_skia_unittest.cc
diff --git a/ui/gfx/image/image_skia_unittest.cc b/ui/gfx/image/image_skia_unittest.cc
index 9d6b29e9fb9567081db5be4e1db73c57fbf3a546..bb6afcca17f985325eb986194f26d40870a5462c 100644
--- a/ui/gfx/image/image_skia_unittest.cc
+++ b/ui/gfx/image/image_skia_unittest.cc
@@ -27,7 +27,7 @@ namespace {
 
 class FixedSource : public ImageSkiaSource {
  public:
-  FixedSource(const ImageSkiaRep& image) : image_(image) {}
+  explicit FixedSource(const ImageSkiaRep& image) : image_(image) {}
 
   virtual ~FixedSource() {
   }
@@ -44,7 +44,7 @@ class FixedSource : public ImageSkiaSource {
 
 class DynamicSource : public ImageSkiaSource {
  public:
-  DynamicSource(const gfx::Size& size) : size_(size) {}
+  explicit DynamicSource(const gfx::Size& size) : size_(size) {}
 
   virtual ~DynamicSource() {
   }