overscroll: Allow taking screenshots only in tabbed browsers.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index 8b1f8e985466a3194a7968a1ae47141fa6bdb2d3..f88f9bd45469c3a1371268202804a0a2555d4f90 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -2739,7 +2739,8 @@ void WebContentsImpl::DidNavigate(
     // RenderViewHostManager::DidNavigateMainFrame, because that can change
     // WebContents::GetRenderViewHost to return the new host, instead of the one
     // that may have just been swapped out.
-    controller_.TakeScreenshot();
+    if (delegate_ && delegate_->CanOverscrollContent())
+      controller_.TakeScreenshot();
 
     render_manager_.DidNavigateMainFrame(rvh);
   }