Merge 83056 - Protect against image conversion failure in mac::FaviconForTabContents().

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

Index: chrome/browser/ui/cocoa/tab_contents/favicon_util.mm
===================================================================
--- chrome/browser/ui/cocoa/tab_contents/favicon_util.mm	(revision 83060)
+++ chrome/browser/ui/cocoa/tab_contents/favicon_util.mm	(working copy)
@@ -19,8 +19,14 @@
   // favicon.
   if (contents && contents->FaviconIsValid()) {
     CGColorSpaceRef color_space = base::mac::GetSystemColorSpace();
-    return gfx::SkBitmapToNSImageWithColorSpace(contents->GetFavicon(),
-                                                color_space);
+    NSImage* image =
+        gfx::SkBitmapToNSImageWithColorSpace(contents->GetFavicon(),
+                                             color_space);
+    // The |image| could be nil if the bitmap is null. In that case, fallback
+    // to the default image.
+    if (image) {
+      return image;
+    }
   }
 
   return app::mac::GetCachedImageWithName(@"nav.pdf");