Allow an empty list of page actions.

chrome/common/extensions/extension.cc

Index: chrome/common/extensions/extension.cc
===================================================================
--- chrome/common/extensions/extension.cc	(revision 35891)
+++ chrome/common/extensions/extension.cc	(working copy)
@@ -1079,6 +1079,8 @@
   }
 
   // Initialize page action (optional).
+  DictionaryValue* page_action_value = NULL;
+
   if (source.HasKey(keys::kPageActions)) {
     ListValue* list_value;
     if (!source.GetList(keys::kPageActions, &list_value)) {
@@ -1086,28 +1088,29 @@
       return false;
     }
 
-    if (list_value->GetSize() != 1u) {
+    size_t list_value_length = list_value->GetSize();
+
+    if (list_value_length == 0u) {
+      // A list with zero items is allowed, and is equivalent to not having
+      // a page_actions key in the manifest.  Don't set |page_action_value|.
+    } else if (list_value_length == 1u) {
+      if (!list_value->GetDictionary(0, &page_action_value)) {
+        *error = errors::kInvalidPageAction;
+        return false;
+      }
+    } else {  // list_value_length > 1u.
       *error = errors::kInvalidPageActionsListSize;
       return false;
     }
-
-    DictionaryValue* page_action_value;
-    if (!list_value->GetDictionary(0, &page_action_value)) {
-      *error = errors::kInvalidPageAction;
-      return false;
-    }
-
-    page_action_.reset(
-        LoadExtensionActionHelper(page_action_value, error));
-    if (!page_action_.get())
-      return false;  // Failed to parse page action definition.
   } else if (source.HasKey(keys::kPageAction)) {
-    DictionaryValue* page_action_value;
     if (!source.GetDictionary(keys::kPageAction, &page_action_value)) {
       *error = errors::kInvalidPageAction;
       return false;
     }
+  }
 
+  // If page_action_value is not NULL, then there was a valid page action.
+  if (page_action_value) {
     page_action_.reset(
         LoadExtensionActionHelper(page_action_value, error));
     if (!page_action_.get())
@@ -1117,7 +1120,7 @@
   // Initialize browser action (optional).
   if (source.HasKey(keys::kBrowserAction)) {
     // Restrict extensions to one UI surface.
-    if (source.HasKey(keys::kPageAction) || source.HasKey(keys::kPageActions)) {
+    if (page_action_.get()) {
       *error = errors::kOneUISurfaceOnly;
       return false;
     }