Avoid rotation anchor during transitional fullscreen states.

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 8a38208b82174a374b576187f2450ca2c8b40ac8..c50b9fcd46f824c0f222148b4bc1248d4bed328d 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -1919,7 +1919,7 @@ void WebViewImpl::resizeWithBrowserControls(const WebSize& newSize,
   bool isRotation =
       page()->settings().getMainFrameResizesAreOrientationChanges() &&
       m_size.width && contentsSize().width() && newSize.width != m_size.width &&
-      !m_fullscreenController->isFullscreen();
+      !m_fullscreenController->isFullscreenOrTransitioning();
   m_size = newSize;
 
   FloatSize viewportAnchorCoords(viewportAnchorCoordX, viewportAnchorCoordY);