Revert of Change extension icon load errors to warnings (patchset #8 id:140001 of https://codereview.chromium.org/1537473003/ )

Reason for revert:
file read from wrong thread

Original issue's description:
> Change extension icon load errors to warnings
>
> During the Extension parsing step, check if the icon file exists and if not, remove that entry from the dictionary.
>
> Keep the same check during the validation phase and don't apply the workaround to unpacked extensions. This will more strongly discourage new extensions from making this mistake.
>
> BUG=570249
>
> Committed: https://crrev.com/6e8e7d1c49657e82d0e8f2518ad463794346321b
> Cr-Commit-Position: refs/heads/master@{#366253}

TBR=rdevlin.cronin@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=570249

Review URL: https://codereview.chromium.org/1554583002

Cr-Commit-Position: refs/heads/master@{#367080}

1 files changed, 3 insertions, 2 deletions

diff --git a/extensions/utility/unpacker.cc b/extensions/utility/unpacker.cc
index be0a4b5..c230f82 100644
--- a/extensions/utility/unpacker.cc
+++ b/extensions/utility/unpacker.cc
@@ -187,8 +187,9 @@ bool Unpacker::Run() {
   // Decode any images that the browser needs to display.
   std::set<base::FilePath> image_paths =
       ExtensionsClient::Get()->GetBrowserImagePaths(extension.get());
-  for (const base::FilePath& path : image_paths) {
-    if (!AddDecodedImage(path))
+  for (std::set<base::FilePath>::iterator it = image_paths.begin();
+       it != image_paths.end(); ++it) {
+    if (!AddDecodedImage(*it))
       return false;  // Error was already reported.
   }