osr: Fix crash in RenderWidgetHostImpl::WasHidden (fixes #3834)

patch/patch.cfg

@@ -518,6 +518,9 @@ patches = [
     # Add RenderWidgetHostImpl::SetCompositorForFlingScheduler to fix fling
     # scrolling in OSR mode.
     # https://github.com/chromiumembedded/cef/issues/2745
+    #
+    # Fix crash in RenderWidgetHostImpl::WasHidden when closing OSR browser.
+    # https://github.com/chromiumembedded/cef/issues/3834
     'name': 'osr_fling_2745',
   },
   {

patch/patches/osr_fling_2745.patch

@@ -56,9 +56,18 @@ index f1030a744809c..c222a209949e6 100644
      return nullptr;
    }
 diff --git content/browser/renderer_host/render_widget_host_impl.cc content/browser/renderer_host/render_widget_host_impl.cc
-index e8f68eca2104c..dded892de5ce4 100644
+index e8f68eca2104c..c579cff86fbbb 100644
 --- content/browser/renderer_host/render_widget_host_impl.cc
 +++ content/browser/renderer_host/render_widget_host_impl.cc
+@@ -791,7 +791,7 @@ void RenderWidgetHostImpl::WasHidden() {
+ 
+   // Cancel pending pointer lock requests, unless there's an open user prompt.
+   // Prompts should remain open and functional across tab switches.
+-  if (!delegate_->IsWaitingForPointerLockPrompt(this)) {
++  if (!delegate_ || !delegate_->IsWaitingForPointerLockPrompt(this)) {
+     RejectPointerLockOrUnlockIfNecessary(
+         blink::mojom::PointerLockResult::kWrongDocument);
+   }
 @@ -3248,6 +3248,11 @@ void RenderWidgetHostImpl::DecrementInFlightEventCount(
    }
  }