Enable DCHECKs by default in non-official builds.

ios/web/web_state/ui/wk_web_view_configuration_provider.mm

Index: ios/web/web_state/ui/wk_web_view_configuration_provider.mm
diff --git a/ios/web/web_state/ui/wk_web_view_configuration_provider.mm b/ios/web/web_state/ui/wk_web_view_configuration_provider.mm
index e3386c5b0ad89d12ccc5f5c55095f40c906879fe..2380b4e528f29d5c3f86dac25d12e4b774500385 100644
--- a/ios/web/web_state/ui/wk_web_view_configuration_provider.mm
+++ b/ios/web/web_state/ui/wk_web_view_configuration_provider.mm
@@ -87,18 +87,20 @@ WKWebViewConfigurationProvider::GetScriptMessageRouter() {
 
 void WKWebViewConfigurationProvider::Purge() {
   DCHECK([NSThread isMainThread]);
-#if !defined(NDEBUG) || !defined(DCHECK_ALWAYS_ON)  // Matches DCHECK_IS_ON.

[sdefresne, 2017/05/16 16:03:52]

I think this should instead use DCHECK_IS_ON() (see base/logging.h line 762-766)
so that this code is enabled when "is_debug = true" even if "dcheck_always_on =
false".

#if DCHECK_IS_ON()
 ...
#endif  // DCHECK_IS_ON()

[gab, 2017/05/16 16:31:43]

Ah right, that's what I intended to use, somehow got side-tracked by previous
code.

Thanks, done!

+#if defined(DCHECK_ALWAYS_ON)
   base::WeakNSObject<id> weak_configuration(configuration_);
   base::WeakNSObject<id> weak_router(router_);
   base::WeakNSObject<id> weak_process_pool([configuration_ processPool]);
-#endif  // !defined(NDEBUG) || defined(DCHECK_ALWAYS_ON)
+#endif  // defined(DCHECK_ALWAYS_ON)
   configuration_.reset();
   router_.reset();
   // Make sure that no one retains configuration, router, processPool.
+#if defined(DCHECK_ALWAYS_ON)
   DCHECK(!weak_configuration);
   DCHECK(!weak_router);
   // TODO(crbug.com/522672): Enable this DCHECK.
   // DCHECK(!weak_process_pool);
+#endif  // defined(DCHECK_ALWAYS_ON)
 }
 
 }  // namespace web