Add external extensions json source in proper mac location.

chrome/browser/extensions/external_pref_extension_loader.cc

Index: chrome/browser/extensions/external_pref_extension_loader.cc
diff --git a/chrome/browser/extensions/external_pref_extension_loader.cc b/chrome/browser/extensions/external_pref_extension_loader.cc
index 8d90ee7249c19adf2ae7bd746cc885ed8504427d..bcd47d580257b3b50d4e6978a65d0588438aee90 100644
--- a/chrome/browser/extensions/external_pref_extension_loader.cc
+++ b/chrome/browser/extensions/external_pref_extension_loader.cc
@@ -7,7 +7,9 @@
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
+#include "base/metrics/histogram.h"
 #include "base/path_service.h"
+#include "chrome/common/chrome_paths.h"
 #include "content/browser/browser_thread.h"
 #include "content/common/json_value_serializer.h"
 
@@ -34,8 +36,10 @@ DictionaryValue* ExtractPrefs(const FilePath& path,
 
 }  // namespace
 
-ExternalPrefExtensionLoader::ExternalPrefExtensionLoader(int base_path_key)
-    : base_path_key_(base_path_key) {
+ExternalPrefExtensionLoader::ExternalPrefExtensionLoader(int base_path_key,
+                                                         Options options)
+    : base_path_key_(base_path_key),
+      options_(options){
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 }
 
@@ -72,8 +76,18 @@ void ExternalPrefExtensionLoader::LoadOnFileThread() {
         base_path_.Append(FILE_PATH_LITERAL("external_extensions.json"));
 
     if (file_util::PathExists(json_file)) {
-      JSONFileValueSerializer serializer(json_file);
-      prefs.reset(ExtractPrefs(json_file, &serializer));
+      if (IsOptionSet(ENSURE_PATH_CONTROLLED_BY_ADMIN) &&
+          !file_util::IsPathControlledByAdmin(json_file)) {
+        LOG(ERROR) << "Can not read external extensions source.  The file "
+                   << json_file.value() << " and every directory in its path "
+                   << "must be owned by root, and not be writable by all "
+                   << "users. This restriction prevents unprivleged users "
+                   << "from making chrome install extensions on other users' "
+                   << "accounts.";
+      } else {
+        JSONFileValueSerializer serializer(json_file);
+        prefs.reset(ExtractPrefs(json_file, &serializer));
+      }
     }
   }
 
@@ -82,6 +96,24 @@ void ExternalPrefExtensionLoader::LoadOnFileThread() {
 
   prefs_.reset(prefs.release());
 
+  // We want to deprecate the external extensions file inside the app
+  // bundle on mac os.  Use a histogram to see how many extensions
+  // are installed using the deprecated path, and how many are installed
+  // from the supported path.  We can use this data to measure the
+  // effectiveness of asking developers to use the new path, or any
+  // automatic migration methods we implement.
+#if defined(OS_MACOSX)
+  // The deprecated path only exists on mac for now.
+  if (base_path_key_ == chrome::DIR_DEPRICATED_EXTERNAL_EXTENSIONS) {
+    UMA_HISTOGRAM_COUNTS_100("Extensions.DepricatedExternalJsonCount",
+                             prefs_->size());
+  }
+#endif  // defined(OS_MACOSX)
+  if (base_path_key_ == chrome::DIR_EXTERNAL_EXTENSIONS) {
+    UMA_HISTOGRAM_COUNTS_100("Extensions.ExternalJsonCount",
+                             prefs_->size());
+  }
+
   // If we have any records to process, then we must have
   // read the .json file.  If we read the .json file, then
   // we were should have set |base_path_|.