Propagate inert state to OOPIFs when a modal dialog is active

third_party/WebKit/Source/core/frame/RemoteFrame.h

Index: third_party/WebKit/Source/core/frame/RemoteFrame.h
diff --git a/third_party/WebKit/Source/core/frame/RemoteFrame.h b/third_party/WebKit/Source/core/frame/RemoteFrame.h
index 19830393658de863271a99d617b750a8f7daf1dc..75fef6ac43be5cdc51447894a37a197947bd3fee 100644
--- a/third_party/WebKit/Source/core/frame/RemoteFrame.h
+++ b/third_party/WebKit/Source/core/frame/RemoteFrame.h
@@ -38,6 +38,8 @@ class CORE_EXPORT RemoteFrame final : public Frame {
   void PrintNavigationWarning(const String&) override {}
   bool PrepareForCommit() override;
   bool ShouldClose() override;
+  void SetIsInert(bool) override;
+  bool IsInert() const override { return last_inert_state_; }
 
   void SetWebLayer(WebLayer*);
   WebLayer* GetWebLayer() const { return web_layer_; }
@@ -64,6 +66,7 @@ class CORE_EXPORT RemoteFrame final : public Frame {
   Member<RemoteFrameView> view_;
   Member<RemoteSecurityContext> security_context_;
   WebLayer* web_layer_ = nullptr;
+  bool last_inert_state_;
 };
 
 inline RemoteFrameView* RemoteFrame::View() const {