Propagate pageScaleFactor to GuestViews

components/guest_view/browser/guest_view_base.cc

Index: components/guest_view/browser/guest_view_base.cc
diff --git a/components/guest_view/browser/guest_view_base.cc b/components/guest_view/browser/guest_view_base.cc
index 063850e6ed8784cf088798f7674298a13ea1bf46..38f41a226115418d8ef026134a0eec5daed78c0b 100644
--- a/components/guest_view/browser/guest_view_base.cc
+++ b/components/guest_view/browser/guest_view_base.cc
@@ -46,7 +46,8 @@ SetSizeParams::~SetSizeParams() {
 
 // This observer ensures that the GuestViewBase destroys itself when its
 // embedder goes away. It also tracks when the embedder's fullscreen is
-// toggled so the guest can change itself accordingly.
+// toggled or when its page scale factor changes so the guest can change
+// itself accordingly.
 class GuestViewBase::OwnerContentsObserver : public WebContentsObserver {
  public:
   OwnerContentsObserver(GuestViewBase* guest,
@@ -100,6 +101,13 @@ class GuestViewBase::OwnerContentsObserver : public WebContentsObserver {
     }
   }
 
+  void OnPageScaleFactorChanged(float page_scale_factor) override {
+    if (destroyed_)
+      return;
+
+    guest_->web_contents()->SetPageScale(page_scale_factor);
+  }
+
  private:
   bool is_fullscreen_;
   bool destroyed_;