Implementing chrome.i18n.getMessage call, that loads message from the extensi...

chrome/test/data/extensions/api_test/i18n/_locales/en_US/messages.json

+{
+  "chrome_extension_name": {
+    "message": "Api test extension"
+  },
+  "simple_message": {
+    "message": "Simple message"
+  },
+  "message_with_one_placeholder": {
+    "message": "Number of errors: $NR_OF_ERRORS$",
+    "placeholders": {
+      "nr_of_errors": {
+        "content": "$1"
+      }
+    }
+  },
+  "message_with_placeholders": {
+    "message": "$Cira$ and $Somebody$ work for $GOOGLE$",
+    "placeholders": {
+      "cira": {
+        "content": "$1"
+      },
+      "somebody": {
+        "content": "$2"
+      },
+      "google": {
+        "content": "Google"
+      }
+    }
+  }
+}