A few minor changes to the chrome.downloads extension API

chrome/renderer/resources/extensions/downloads_custom_bindings.js

Index: chrome/renderer/resources/extensions/downloads_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/downloads_custom_bindings.js b/chrome/renderer/resources/extensions/downloads_custom_bindings.js
index be7d1c42cbd23248b6ee856e1e09d1e92b18c655..88efbac64dea41723e01a8c293695b6bc3b80832 100644
--- a/chrome/renderer/resources/extensions/downloads_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/downloads_custom_bindings.js
@@ -16,19 +16,36 @@ eventBindings.registerArgumentMassager(
   // Copy the id so that extensions can't change it.
   var downloadId = downloadItem.id;
   var suggestable = true;
+  function isValidResult(result) {
+    if (result === undefined)
+      return false;
+    if (typeof(result) != 'object') {
+      console.error('Error: Invocation of form suggest(' + typeof(result) +
+                    ') doesn\'t match definition suggest({filename: string, ' +
+                    'conflictAction: string})');
+      return false;
+    } else if ((typeof(result.filename) != 'string') ||
+               (result.filename.length == 0)) {
+      console.error('Error: "filename" parameter to suggest() must be a ' +
+                    'non-empty string');
+      return false;
+    } else if ([undefined, 'uniquify', 'overwrite', 'prompt'].indexOf(
+                 result.conflictAction) < 0) {
+      console.error('Error: "conflictAction" parameter to suggest() must be ' +
+                    'one of undefined, "uniquify", "overwrite", "prompt"');
+      return false;
+    }
+    return true;
+  }
   function suggestCallback(result) {
     if (!suggestable) {
       console.error('suggestCallback may not be called more than once.');
       return;
     }
     suggestable = false;
-    if ((typeof(result) == 'object') &&
-        result.filename &&
-        (typeof(result.filename) == 'string') &&
-        ((result.conflict_action == undefined) ||
-          (typeof(result.conflict_action) == 'string'))) {
+    if (isValidResult(result)) {
       downloadsInternal.determineFilename(
-          downloadId, result.filename, result.conflict_action || "");
+          downloadId, result.filename, result.conflictAction || "");
     } else {
       downloadsInternal.determineFilename(downloadId, "", "");
     }