Reset scroll and scale while toggling "Request desktop site"

third_party/WebKit/Source/web/WebViewImpl.cpp

Index: third_party/WebKit/Source/web/WebViewImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebViewImpl.cpp b/third_party/WebKit/Source/web/WebViewImpl.cpp
index 25ac5094e6346d6e8c8e380599cbe1ed867760e5..3f3ec4a69eb24a87555176a97befe349c65c982d 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -79,6 +79,7 @@
 #include "core/layout/TextAutosizer.h"
 #include "core/layout/api/LayoutViewItem.h"
 #include "core/layout/compositing/PaintLayerCompositor.h"
+#include "core/loader/DocumentLoader.h"
 #include "core/loader/FrameLoadRequest.h"
 #include "core/loader/FrameLoader.h"
 #include "core/loader/FrameLoaderStateMachine.h"
@@ -3314,6 +3315,9 @@ void WebViewImpl::ResetScrollAndScaleState() {
       scrollable_area->SetScrollOffset(ScrollOffset(), kProgrammaticScroll);
   }
 
+  if (Document* document = ToLocalFrame(GetPage()->MainFrame())->GetDocument())
+    document->Loader()->GetHistoryItem()->SetDidSaveScrollOrScaleState(false);

[aelias_OOO_until_Jul13, 2017/06/06 02:57:30]

This seems reasonable to me.  Could you add a unit test?  I suggest adding one
in WebViewTest.cpp, see for example related test
WebViewTest.HistoryResetScrollAndScaleState.

+
   GetPageScaleConstraintsSet().SetNeedsReset(true);
 }