Beginning of support for extension content verification

extensions/browser/extension_system.cc

Index: extensions/browser/extension_system.cc
diff --git a/extensions/browser/extension_system.cc b/extensions/browser/extension_system.cc
index fc2abc0a8f0eef1be6dfb1f9bab7cd2aba9e650a..1b1b224361da3f4c0f255b09c500cee7a43102ff 100644
--- a/extensions/browser/extension_system.cc
+++ b/extensions/browser/extension_system.cc
@@ -23,4 +23,8 @@ ExtensionSystem* ExtensionSystem::Get(content::BrowserContext* context) {
       ->GetForBrowserContext(context);
 }
 
+ContentVerifier* ExtensionSystem::content_verifier() {
+  return NULL;

[Yoyo Zhou, 2014/05/07 02:25:59]

Most of the other members of this class don't provide a default NULL
implementation. Why do it here?

[asargent_no_longer_on_chrome, 2014/05/07 06:56:42]

Huh, I guess I was sort of thinking along the lines of this documenting the fact
that content verification is an optional feature and the rest of the
ExtensionSystem doesn't depend on having a non-null ContentVerifier, so other
kinds of ExtensionSystem's don't have to provide one if they don't want to. 

But you make a good point about this going against the prevailing style, so I've
changed it to be pure virtual and added the NULL-returning version in the other
subclasses of ExtensionSystem. 

+}
+
 }  // namespace extensions