Implementation for feature policy - fullscreen

third_party/WebKit/Source/core/dom/Fullscreen.cpp

Index: third_party/WebKit/Source/core/dom/Fullscreen.cpp
diff --git a/third_party/WebKit/Source/core/dom/Fullscreen.cpp b/third_party/WebKit/Source/core/dom/Fullscreen.cpp
index ff1331bd4cadc423dc311e1626746ce7ce733867..7b9a621be3a3144b57e76bbc7df07c7e082a82ce 100644
--- a/third_party/WebKit/Source/core/dom/Fullscreen.cpp
+++ b/third_party/WebKit/Source/core/dom/Fullscreen.cpp
@@ -29,6 +29,7 @@
 
 #include "core/dom/Fullscreen.h"
 
+#include "bindings/core/v8/ConditionalFeatures.h"
 #include "core/dom/Document.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/StyleEngine.h"
@@ -100,7 +101,20 @@ bool allowedToRequestFullscreen(Document& document) {
 }
 
 // https://fullscreen.spec.whatwg.org/#fullscreen-is-supported
-bool fullscreenIsSupported(const Document& document) {
+// TODO(lunalu): update the placement of the feature policy code once it is in
+// https://fullscreen.spec.whatwg.org/.
+bool fullscreenIsSupported(Document& document) {
+  Frame* frame = document.frame();

[foolip, 2016/12/02 10:52:09]

document.frame() returns a LocalFrame*, so you can use that and skip the DCHECK
and cast.

I think all call sites guarantee that document.frame() can't be null here, but
that's a bit brittle, so I'd say also throw in `if (!frame) return false`;

[lunalu1, 2016/12/02 19:22:07]

Done.

+  DCHECK(frame->isLocalFrame());
+  if (!isFeatureEnabledInFrame(blink::kFullscreenFeature,
+                               toLocalFrame(frame))) {
+    if (RuntimeEnabledFeatures::featurePolicyEnabled()) {
+      document.addConsoleMessage(ConsoleMessage::create(
+          JSMessageSource, WarningMessageLevel,
+          "Fullscreen API is disabled by feature policy for this frame"));
+      return false;
+    }
+  }
   // Fullscreen is supported if there is no previously-established user
   // preference, security risk, or platform limitation.
   return !document.settings() || document.settings()->fullscreenSupported();