Fall back to the default favicon on invalid favicon files.

I regressed this in r149891.

BUG=140689

Review URL: https://chromiumcodereview.appspot.com/10853018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150092 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/cocoa/tab_contents/favicon_util_mac.mm

@@ -13,7 +13,7 @@ namespace mac {
 
 NSImage* FaviconForTabContents(TabContents* contents) {
   if (contents && contents->favicon_tab_helper()->FaviconIsValid()) {
-    NSImage* image = contents->favicon_tab_helper()->GetFavicon().ToNSImage();
+    NSImage* image = contents->favicon_tab_helper()->GetFavicon().AsNSImage();
     // The |image| could be nil if the bitmap is null. In that case, fallback
     // to the default image.
     if (image) {

ui/gfx/image/image.cc

@@ -342,9 +342,15 @@ SkBitmap Image::AsBitmap() const {
 }
 
 ImageSkia Image::AsImageSkia() const {
-  return IsEmpty() ? ImageSkia(SkBitmap()) : *ToImageSkia();
+  return IsEmpty() ? ImageSkia() : *ToImageSkia();
 }
 
+#if defined(OS_MACOSX)
+NSImage* Image::AsNSImage() const {
+  return IsEmpty() ? nil : ToNSImage();
+}
+#endif
+
 ImageSkia* Image::CopyImageSkia() const {
   return new ImageSkia(*ToImageSkia());
 }

ui/gfx/image/image.h

@@ -97,7 +97,7 @@ class UI_EXPORT Image {
 
   // Converts the Image to the desired representation and stores it internally.
   // The returned result is a weak pointer owned by and scoped to the life of
-  // the Image.
+  // the Image. Must only be called if IsEmpty() is false.
   const SkBitmap* ToSkBitmap() const;
   const ImageSkia* ToImageSkia() const;
 #if defined(TOOLKIT_GTK)
@@ -110,10 +110,15 @@ class UI_EXPORT Image {
   // Same as ToSkBitmap(), but returns a null SkBitmap if this image is empty.
   SkBitmap AsBitmap() const;
 
-  // Same as ToSkBitmap(), but returns a ImageSkia with a null SkBitmap if this
+  // Same as ToImageSkia(), but returns an empty ImageSkia if this
   // image is empty.
   ImageSkia AsImageSkia() const;
 
+#if defined(OS_MACOSX)
+  // Same as ToSkBitmap(), but returns nil if this image is empty.
+  NSImage* AsNSImage() const;
+#endif
+
   // Performs a conversion, like above, but returns a copy of the result rather
   // than a weak pointer. The caller is responsible for deleting the result.
   // Note that the result is only a copy in terms of memory management; the