Clean up handling of autosizing state changes.

Source/web/WebViewImpl.cpp

Index: Source/web/WebViewImpl.cpp
diff --git a/Source/web/WebViewImpl.cpp b/Source/web/WebViewImpl.cpp
index 694ceb68b9ec095754f19930561676f4d890fb94..6c03de3b9a11624bd702491a06f6dc70b4242e5f 100644
--- a/Source/web/WebViewImpl.cpp
+++ b/Source/web/WebViewImpl.cpp
@@ -113,6 +113,7 @@
 #include "core/page/PointerLockController.h"
 #include "core/page/ScopedPageLoadDeferrer.h"
 #include "core/page/TouchDisambiguation.h"
+#include "core/rendering/FastTextAutosizer.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/RenderWidget.h"
 #include "core/rendering/TextAutosizer.h"
@@ -2871,6 +2872,11 @@ void WebViewImpl::updatePageDefinedViewportConstraints(const ViewportDescription
     }
 
     updateMainFrameLayoutSize();
+
+    if (LocalFrame* frame = page()->mainFrame()) {
+        if (FastTextAutosizer* textAutosizer = frame->document()->fastTextAutosizer())
+            textAutosizer->updatePageInfoInAllFrames();
+    }
 }
 
 void WebViewImpl::updateMainFrameLayoutSize()