Change Picture: Fix selection of image from file.

Images from files are typically not PNG so we can't rely
on image bytes to be available. Check format and bytes
when selecting image type 'old' to fix this.

Test: DCHECKs passes when selecting image from file in settings
Bug: 
Change-Id: I00ac5ff27520e6a7de249e3fb4a9a4c6c9663e7b
Reviewed-on: https://chromium-review.googlesource.com/804855Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: David Reveman <reveman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521163}

chrome/browser/ui/webui/settings/chromeos/change_picture_handler.cc

@@ -298,10 +298,16 @@ void ChangePictureHandler::HandleSelectImage(const base::ListValue* args) {
   if (image_type == "old") {
     // Previous image (from camera or manually uploaded) re-selected.
     DCHECK(!previous_image_.isNull());
-    std::unique_ptr<user_manager::UserImage> user_image =
-        base::MakeUnique<user_manager::UserImage>(
-            previous_image_, previous_image_bytes_, previous_image_format_);
-    user_image->MarkAsSafe();
+    std::unique_ptr<user_manager::UserImage> user_image;
+    if (previous_image_format_ == user_manager::UserImage::FORMAT_PNG &&
+        previous_image_bytes_) {
+      user_image = base::MakeUnique<user_manager::UserImage>(
+          previous_image_, previous_image_bytes_, previous_image_format_);
+      user_image->MarkAsSafe();
+    } else {
+      user_image = user_manager::UserImage::CreateAndEncode(
+          previous_image_, user_manager::UserImage::FORMAT_JPEG);
+    }
     user_image_manager->SaveUserImage(std::move(user_image));
 
     UMA_HISTOGRAM_EXACT_LINEAR("UserImage.ChangeChoice",