Avoid crashing when an ImageSkia has no representations and is converted to SkBitmap.

Review URL: https://chromiumcodereview.appspot.com/10828296

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151570 0039d316-1c4b-4281-b951-d872f2087c98

ui/gfx/image/image_skia.cc

@@ -165,13 +165,6 @@ ImageSkia& ImageSkia::operator=(const SkBitmap& other) {
   return *this;
 }
 
-ImageSkia::operator SkBitmap&() const {
-  if (isNull())
-    return const_cast<SkBitmap&>(NullImageRep().sk_bitmap());
-
-  return const_cast<SkBitmap&>(storage_->image_reps()[0].sk_bitmap());
-}
-
 ImageSkia::~ImageSkia() {
 }
 
@@ -279,16 +272,18 @@ std::vector<ImageSkiaRep> ImageSkia::image_reps() const {
   return image_reps;
 }
 
-const SkBitmap* ImageSkia::bitmap() const {
+ImageSkia::operator SkBitmap&() const {
   if (isNull()) {
     // Callers expect a ImageSkiaRep even if it is |isNull()|.
     // TODO(pkotwicz): Fix this.
-    return &NullImageRep().sk_bitmap();
+    return NullImageRep().mutable_sk_bitmap();
   }
 
   ImageSkiaReps::iterator it =
       storage_->FindRepresentation(ui::SCALE_FACTOR_100P, true);
-  return &it->sk_bitmap();
+  if (it != storage_->image_reps().end())
+    return it->mutable_sk_bitmap();
+  return NullImageRep().mutable_sk_bitmap();
 }
 
 void ImageSkia::Init(const ImageSkiaRep& image_rep) {

ui/gfx/image/image_skia.h

@@ -113,7 +113,7 @@ class UI_EXPORT ImageSkia {
   // This function should only be used in unittests and on platforms which do
   // not support scale factors other than 1x.
   // TODO(pkotwicz): Return null SkBitmap when the object has no 1x bitmap.
-  const SkBitmap* bitmap() const;
+  const SkBitmap* bitmap() const { return &operator SkBitmap&(); }
 
   // Returns a vector with the image reps contained in this object.
   // There is no guarantee that this will return all images rep for

ui/gfx/image/image_skia_rep.h

@@ -46,6 +46,9 @@ class UI_EXPORT ImageSkiaRep {
   const SkBitmap& sk_bitmap() const { return bitmap_; }
 
  private:
+  friend class ImageSkia;
+  SkBitmap& mutable_sk_bitmap() { return bitmap_; }
+
   SkBitmap bitmap_;
   ui::ScaleFactor scale_factor_;
 };

ui/gfx/image/image_skia_unittest.cc

@@ -173,4 +173,27 @@ TEST(ImageSkiaTest, GetBitmap) {
   EXPECT_FALSE(bitmap->isNull());
 }
 
+TEST(ImageSkiaTest, GetBitmapFromEmpty) {
+  // Create an image with 1 representation and remove it so the ImageSkiaStorage
+  // is left with no representations.
+  ImageSkia empty_image(ImageSkiaRep(Size(100, 200), ui::SCALE_FACTOR_100P));
+  ImageSkia empty_image_copy(empty_image);
+  empty_image.RemoveRepresentation(ui::SCALE_FACTOR_100P);
+
+  // Check that ImageSkia::bitmap() still returns a valid SkBitmap pointer for
+  // the image and all its copies.
+  const SkBitmap* bitmap = empty_image_copy.bitmap();
+  ASSERT_NE(static_cast<SkBitmap*>(NULL), bitmap);
+  EXPECT_TRUE(bitmap->isNull());
+  EXPECT_TRUE(bitmap->empty());
+}
+
+TEST(ImageSkiaTest, OperatorBitmapFromSource) {
+  ImageSkia image_skia(new DynamicSource(Size(100, 200)), Size(100, 200));
+  // ImageSkia should use the source to create the bitmap.
+  const SkBitmap& bitmap = image_skia;
+  ASSERT_NE(static_cast<SkBitmap*>(NULL), &bitmap);
+  EXPECT_FALSE(bitmap.isNull());
+}
+
 }  // namespace gfx