Make the navigator.usb attribute accessible only in secure contexts.

third_party/WebKit/Source/bindings/modules/v8/ConditionalFeaturesForModules.cpp

Index: third_party/WebKit/Source/bindings/modules/v8/ConditionalFeaturesForModules.cpp
diff --git a/third_party/WebKit/Source/bindings/modules/v8/ConditionalFeaturesForModules.cpp b/third_party/WebKit/Source/bindings/modules/v8/ConditionalFeaturesForModules.cpp
index 01dfe2131078787db58d8bc78768ce779802999a..e7ac3bb1d9c71c50b705bcab82b1f4c9a2db5145 100644
--- a/third_party/WebKit/Source/bindings/modules/v8/ConditionalFeaturesForModules.cpp
+++ b/third_party/WebKit/Source/bindings/modules/v8/ConditionalFeaturesForModules.cpp
@@ -55,7 +55,9 @@ void installConditionalFeaturesForModules(
                                           v8::Local<v8::Object>(),
                                           prototypeObject, interfaceObject);
     }
-    if (OriginTrials::webUSBEnabled(executionContext)) {
+    // Mimics the [SecureContext] extended attribute.
+    if (OriginTrials::webUSBEnabled(executionContext) &&
+        executionContext->isSecureContext()) {

[chasej, 2017/02/22 19:34:18]

The check for secure context is redundant. Origin trials are already
limited to secure contexts. So, the OriginTrials::webUSBEnabled()
method will return false if it is not a secure context.

       V8NavigatorPartial::installWebUSB(isolate, world, v8::Local<v8::Object>(),
                                         prototypeObject, interfaceObject);
     }
@@ -69,7 +71,9 @@ void installConditionalFeaturesForModules(
       V8WindowPartial::installImageCapture(isolate, world, instanceObject,
                                            prototypeObject, interfaceObject);
     }
-    if (OriginTrials::webUSBEnabled(executionContext)) {
+    // Mimics the [SecureContext] extended attribute.
+    if (OriginTrials::webUSBEnabled(executionContext) &&
+        executionContext->isSecureContext()) {

[chasej, 2017/02/22 19:34:18]

Ditto.

       V8WindowPartial::installWebUSB(isolate, world, instanceObject,
                                      prototypeObject, interfaceObject);
     }