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

ui/gfx/image/image_skia_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/image/image_skia.h"
 
 #include "base/logging.h"
 #include "base/threading/simple_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/base/layout.h"
 #include "ui/gfx/image/image_skia_rep.h"
 #include "ui/gfx/image/image_skia_source.h"
 #include "ui/gfx/size.h"
 
 // Duplicated from base/threading/non_thread_safe.h so that we can be
 // good citizens there and undef the macro.
 #if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
 #define ENABLE_NON_THREAD_SAFE 1
 #else
 #define ENABLE_NON_THREAD_SAFE 0
 #endif
 
 namespace gfx {
 
 namespace {
 
 class FixedSource : public ImageSkiaSource {
  public:
-  FixedSource(const ImageSkiaRep& image) : image_(image) {}
+  explicit FixedSource(const ImageSkiaRep& image) : image_(image) {}
 
   virtual ~FixedSource() {
   }
 
   virtual ImageSkiaRep GetImageForScale(ui::ScaleFactor scale_factor) OVERRIDE {
     return image_;
   }
 
  private:
   ImageSkiaRep image_;
 
   DISALLOW_COPY_AND_ASSIGN(FixedSource);
 };
 
 class DynamicSource : public ImageSkiaSource {
  public:
-  DynamicSource(const gfx::Size& size) : size_(size) {}
+  explicit DynamicSource(const gfx::Size& size) : size_(size) {}
 
   virtual ~DynamicSource() {
   }
 
   virtual ImageSkiaRep GetImageForScale(ui::ScaleFactor scale_factor) OVERRIDE {
     return gfx::ImageSkiaRep(size_, scale_factor);
   }
 
  private:
   gfx::Size size_;
@@ skipping 315 matching lines @@
   EXPECT_FALSE(threadsafe_on_thread.can_modify());
   EXPECT_TRUE(image.CanRead());
   EXPECT_FALSE(image.CanModify());
 }
 #endif  // ENABLE_NON_THREAD_SAFE
 
 // Just in case we ever get lumped together with other compilation units.
 #undef ENABLE_NON_THREAD_SAFE
 
 }  // namespace gfx