Notify in console when an API fails because it needs to be invoked on user action.

Source/core/page/PointerLockController.cpp

Index: Source/core/page/PointerLockController.cpp
diff --git a/Source/core/page/PointerLockController.cpp b/Source/core/page/PointerLockController.cpp
index 8fe61a2b9d856ee3161823457530778e31b82dbc..3a58ecc4d1ecbccf3685b3b1d37ba789ebda2b27 100644
--- a/Source/core/page/PointerLockController.cpp
+++ b/Source/core/page/PointerLockController.cpp
@@ -49,6 +49,11 @@ PassOwnPtrWillBeRawPtr<PointerLockController> PointerLockController::create(Page
 
 void PointerLockController::requestPointerLock(Element* target)
 {
+    if (!UserGestureIndicator::processingUserGesture()) {
+        target->document().executionContext()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, WarningMessageLevel,
+            "requestPointerLock can only be initiated by a user gesture."));

[Mike West, 2014/09/29 12:24:08]

Same here.

[Mayur Kankanwadi, 2014/09/30 13:56:40]

Done.

+    }

[Mike West, 2014/09/29 12:24:08]

You should return early here, right? Otherwise you're not actually blocking the
execution.

[Mayur Kankanwadi, 2014/09/30 13:56:40]

The existing code flow does not do anything noticing the request was not
initiated by user gesture. 
We are just doing a check for posting the console message. There is no intention
to change the existing flow in anyway.

[Mike West, 2014/09/30 14:18:11]

Then I don't understand why you're adding a message. You're saying "Hey, you can
only do this in the context of a user gesture!" but then you let the execution
continue.

Why?

+
     if (!target || !target->inDocument() || m_documentOfRemovedElementWhileWaitingForUnlock) {
         enqueueEvent(EventTypeNames::pointerlockerror, target);
         return;