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..a1969cd2a570421f9dd0e2b76b255a65b20d5433 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"
@@ -100,10 +101,38 @@ 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) {
+  LocalFrame* frame = document.frame();
+  if (!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();
+  bool fullscreenSupported =
+      !document.settings() || document.settings()->fullscreenSupported();
+
+  if (!RuntimeEnabledFeatures::featurePolicyEnabled()) {
+    return fullscreenSupported;
+  }
+
+  if (fullscreenSupported) {

[iclelland, 2016/12/05 20:48:30]

Can we add a comment here? Something like

"If FeaturePolicy is enabled, then check that fullscreen was not disabled by
policy in the parent frame"

(And a TODO comment to clean all of this up once iframe attributes are supported
for feature policy)

[lunalu1, 2016/12/05 21:07:32]

Done.

+    if (frame->tree()
+            .parent()
+            ->securityContext()
+            ->getFeaturePolicy()
+            ->isFeatureEnabled(kFullscreenFeature)) {
+      return true;
+    }
+  } else if (isFeatureEnabledInFrame(kFullscreenFeature, frame)) {

[iclelland, 2016/12/05 20:48:30]

And I'd add a comment here that says "Even if the iframe attribute is not
present, allow fullscreen to be enabled by feature policy"

[lunalu1, 2016/12/05 21:07:32]

Done.

+    return true;
+  }
+
+  document.addConsoleMessage(ConsoleMessage::create(
+      JSMessageSource, WarningMessageLevel,
+      "Fullscreen API is disabled by feature policy for this frame"));
+  return false;
 }
 
 // https://fullscreen.spec.whatwg.org/#fullscreen-element-ready-check