changeset:   312091:a3fff31b8b70
  user:        Xidorn Quan <quanxunzhen@gmail.com>
  Date:        Thu Apr 14 17:38:13 2016 +1000
  summary:     Bug 1261933 - Continue unlocking pointer even if the widget has gone. r=smaug a=lizzard

  MozReview-Commit-ID: 1siQhemFf9O

diff -r f5e862ea4a72 -r a3fff31b8b70 dom/base/nsDocument.cpp
--- a/dom/base/nsDocument.cpp	Tue May 31 18:35:26 2016 -0700
+++ b/dom/base/nsDocument.cpp	Thu Apr 14 17:38:13 2016 +1000
@@ -12315,49 +12315,37 @@
 bool
 nsDocument::SetPointerLock(Element* aElement, int aCursorStyle)
 {
-  // NOTE: aElement will be nullptr when unlocking.
-  nsCOMPtr<nsPIDOMWindow> window = GetWindow();
-  if (!window) {
-    NS_WARNING("SetPointerLock(): No Window");
-    return false;
-  }
-
-  nsIDocShell *docShell = window->GetDocShell();
-  if (!docShell) {
-    NS_WARNING("SetPointerLock(): No DocShell (window already closed?)");
-    return false;
-  }
-
-  nsRefPtr<nsPresContext> presContext;
-  docShell->GetPresContext(getter_AddRefs(presContext));
-  if (!presContext) {
-    NS_WARNING("SetPointerLock(): Unable to get presContext in \
-                domWindow->GetDocShell()->GetPresContext()");
+  MOZ_ASSERT(!aElement || aElement->OwnerDoc() == this,
+             "We should be either unlocking pointer (aElement is nullptr), "
+             "or locking pointer to an element in this document");
+#ifdef DEBUG
+  if (!aElement) {
+    nsCOMPtr<nsIDocument> pointerLockedDoc =
+      do_QueryReferent(EventStateManager::sPointerLockedDoc);
+    MOZ_ASSERT(pointerLockedDoc == this);
+  }
+#endif
+
+  nsIPresShell* shell = GetShell();
+  if (!shell) {
+    NS_WARNING("SetPointerLock(): No PresShell");
     return false;
   }
-
-  nsCOMPtr<nsIPresShell> shell = presContext->PresShell();
-  if (!shell) {
-    NS_WARNING("SetPointerLock(): Unable to find presContext->PresShell()");
-    return false;
-  }
-
-  nsIFrame* rootFrame = shell->GetRootFrame();
-  if (!rootFrame) {
-    NS_WARNING("SetPointerLock(): Unable to get root frame");
+  nsPresContext* presContext = shell->GetPresContext();
+  if (!presContext) {
+    NS_WARNING("SetPointerLock(): Unable to get PresContext");
     return false;
   }
 
-  nsCOMPtr<nsIWidget> widget = rootFrame->GetNearestWidget();
-  if (!widget) {
-    NS_WARNING("SetPointerLock(): Unable to find widget in \
-                shell->GetRootFrame()->GetNearestWidget();");
-    return false;
-  }
-
-  if (aElement && (aElement->OwnerDoc() != this)) {
-    NS_WARNING("SetPointerLock(): Element not in this document.");
-    return false;
+  nsCOMPtr<nsIWidget> widget;
+  nsIFrame* rootFrame = shell->GetRootFrame();
+  if (!NS_WARN_IF(!rootFrame)) {
+    widget = rootFrame->GetNearestWidget();
+    NS_WARN_IF_FALSE(widget, "SetPointerLock(): Unable to find widget "
+                     "in shell->GetRootFrame()->GetNearestWidget();");
+    if (aElement && !widget) {
+      return false;
+    }
   }
 
   // Hide the cursor and set pointer lock for future mouse events
diff -r f5e862ea4a72 -r a3fff31b8b70 dom/events/EventStateManager.cpp
--- a/dom/events/EventStateManager.cpp	Tue May 31 18:35:26 2016 -0700
+++ b/dom/events/EventStateManager.cpp	Thu Apr 14 17:38:13 2016 +1000
@@ -4128,10 +4128,6 @@
   // NOTE: aElement will be nullptr when unlocking.
   sIsPointerLocked = !!aElement;
 
-  if (!aWidget) {
-    return;
-  }
-
   // Reset mouse wheel transaction
   WheelTransaction::EndTransaction();
 
@@ -4140,6 +4136,8 @@
     do_GetService("@mozilla.org/widget/dragservice;1");
 
   if (sIsPointerLocked) {
+    MOZ_ASSERT(aWidget, "Locking pointer requires a widget");
+
     // Store the last known ref point so we can reposition the pointer after unlock.
     mPreLockPoint = sLastRefPoint;
 
@@ -4164,7 +4162,9 @@
     // pre-pointerlock position, so that the synthetic mouse event reports
     // no movement.
     sLastRefPoint = mPreLockPoint;
-    aWidget->SynthesizeNativeMouseMove(mPreLockPoint + aWidget->WidgetToScreenOffset());
+    if (aWidget) {
+      aWidget->SynthesizeNativeMouseMove(mPreLockPoint + aWidget->WidgetToScreenOffset());
+    }
 
     // Don't retarget events to this element any more.
     nsIPresShell::SetCapturingContent(nullptr, CAPTURE_POINTERLOCK);