Bug 1203151 - Allow disabling of screen wakelocks for video elements. r=baku

dom/html/HTMLVideoElement.cpp

@@ -42,6 +42,7 @@ NS_IMPL_ELEMENT_CLONE(HTMLVideoElement)
 
 HTMLVideoElement::HTMLVideoElement(already_AddRefed<NodeInfo>& aNodeInfo)
   : HTMLMediaElement(aNodeInfo)
+  , mUseScreenWakeLock(true)
 {
 }
 
@@ -186,6 +187,19 @@ bool HTMLVideoElement::MozHasAudio() const
   return HasAudio();
 }
 
+bool HTMLVideoElement::MozUseScreenWakeLock() const
+{
+  MOZ_ASSERT(NS_IsMainThread(), "Should be on main thread.");
+  return mUseScreenWakeLock;
+}
+
+void HTMLVideoElement::SetMozUseScreenWakeLock(bool aValue)
+{
+  MOZ_ASSERT(NS_IsMainThread(), "Should be on main thread.");
+  mUseScreenWakeLock = aValue;
+  UpdateScreenWakeLock();
+}
+
 JSObject*
 HTMLVideoElement::WrapNode(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
 {
@@ -250,14 +264,15 @@ HTMLVideoElement::UpdateScreenWakeLock()
 {
   bool hidden = OwnerDoc()->Hidden();
 
-  if (mScreenWakeLock && (mPaused || hidden)) {
+  if (mScreenWakeLock && (mPaused || hidden || !mUseScreenWakeLock)) {
     ErrorResult rv;
     mScreenWakeLock->Unlock(rv);
     mScreenWakeLock = nullptr;
     return;
   }
 
-  if (!mScreenWakeLock && !mPaused && !hidden && HasVideo()) {
+  if (!mScreenWakeLock && !mPaused && !hidden &&
+      mUseScreenWakeLock && HasVideo()) {
     nsRefPtr<power::PowerManagerService> pmService =
       power::PowerManagerService::GetInstance();
     NS_ENSURE_TRUE_VOID(pmService);