Prevent unnecessary prompts when unpacked extensions use chrome.permissions.request.

chrome/common/extensions/extension.h

Index: chrome/common/extensions/extension.h
diff --git a/chrome/common/extensions/extension.h b/chrome/common/extensions/extension.h
index 97b7930427b0a6fbe46d2cb351f3098dd73a2841..a2ee6e20bbb7f7a85ba9f190fd0de8a1fd5427d7 100644
--- a/chrome/common/extensions/extension.h
+++ b/chrome/common/extensions/extension.h
@@ -396,11 +396,13 @@ class Extension : public base::RefCountedThreadSafe<Extension> {
   const URLPatternSet& GetEffectiveHostPermissions() const;
 
   // Returns true if the extension can silently increase its permission level.
-  // Extensions that can silently increase permissions are installed through
-  // mechanisms that are implicitly trusted.
+  // Users must approve permissions for unpacked and packed extensions in the
+  // following situations:
+  //  - when installing or upgrading packed extensions
+  //  - when installing unpacked extensions that have NPAPI plugins
+  //  - when either type of extension requests optional permissions
   bool CanSilentlyIncreasePermissions() const;
 
-
   // Whether the extension has access to the given URL.
   bool HasHostPermission(const GURL& url) const;