Enable Feature Policy without experimental features or 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 f0e48fbf779f72f15e131b0357344568cdd7f096..62cae8d20feafce876c9684321e708aa2bd79f7d 100644
--- a/third_party/WebKit/Source/core/dom/Fullscreen.cpp
+++ b/third_party/WebKit/Source/core/dom/Fullscreen.cpp
@@ -63,6 +63,26 @@ bool AllowedToUseFullscreen(const Frame* frame) {
   if (!frame)
     return false;
 
+  // TODO(lunalu): Re-enable fullscreen in feature policy once all fullscreen

[iclelland, 2017/05/09 17:58:45]

As mentioned offline, I don't really like this, even for a temporary measure --
and it highlights the fact that we're still doing lots of tests inside the
calling code to see whether featurepolicy wants to handle a feature. Here it's
just if (RuntimeEnabledFeatures::featurePolicyEnabled()), but in vibrate code,
it's (RuntimeEnabledFeatures::featurePolicyEnabled() &&
RuntimeEnabledFeatures::featurePolicyExperimentalFeaturesEnabled()), and in
other code, it could be different, and change whenever we promote a feature from
experimental to stable.

Maybe the right thing to do is have a method in FeaturePolicy.cpp that says
whether FP is currently handling a given feature. Then we can centralize the
featurePolicyEnabled and featurePolicyExperimentalFeaturesEnabled logic, and put
the special case for Fullscreen right there. WDYT?

+  // tests have been re-written that "allowfullscreen" / "fullscreen" policy
+  // cannot be updated dynamically, by replacing the block below by commented
+  // block below.
+  // crbug.com/666761
+  // 2. If |document|'s browsing context is a top-level browsing context, then
+  // return true.
+  if (frame->IsMainFrame())
+    return true;
+
+  // 3. If |document|'s browsing context has a browsing context container that
+  // is an iframe element with an |allowattribute| attribute specified, and
+  // whose node document is allowed to use the feature indicated by
+  // |allowattribute|, then return true.
+  if (frame->Owner() && frame->Owner()->AllowFullscreen())
+    return AllowedToUseFullscreen(frame->Tree().Parent());
+
+  // 4. Return false.
+  return false;
+  /*
   if (!RuntimeEnabledFeatures::featurePolicyEnabled()) {
     // 2. If |document|'s browsing context is a top-level browsing context, then
     // return true.
@@ -83,6 +103,7 @@ bool AllowedToUseFullscreen(const Frame* frame) {
   // 2. If Feature Policy is enabled, return the policy for "fullscreen"
   // feature.
   return frame->IsFeatureEnabled(WebFeaturePolicyFeature::kFullscreen);
+  */
 }
 
 bool AllowedToRequestFullscreen(Document& document) {