Set AllowOverlappingViews for history overlay

chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm

Index: chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
diff --git a/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm b/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
index 17dac1bc613953e2cb4025c1aaf4e1b70011a141..1795fc06b2f0ab951150f5c167b81a5902eba023 100644
--- a/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
+++ b/chrome/browser/renderer_host/chrome_render_widget_host_view_mac_delegate.mm
@@ -179,6 +179,10 @@ class SpellCheckRenderViewObserver : public content::RenderViewHostObserver {
         ((shouldGoBack && canGoBack && !isRightScroll) ||
          (shouldGoForward && canGoForward && isRightScroll))) {
 
+      BrowserWindowController* windowController =
+          [BrowserWindowController browserWindowControllerForView:
+                  renderWidgetHost_->GetView()->GetNativeView()];
+
       // Released by the tracking handler once the gesture is complete.
       HistoryOverlayController* historyOverlay =
           [[HistoryOverlayController alloc]
@@ -218,6 +222,7 @@ class SpellCheckRenderViewObserver : public content::RenderViewHostObserver {
           if (phase == NSEventPhaseBegan) {
             [historyOverlay showPanelForView:
                 renderWidgetHost_->GetView()->GetNativeView()];
+            [windowController onHistoryOverlayShown];
             return;
           }
 
@@ -239,8 +244,10 @@ class SpellCheckRenderViewObserver : public content::RenderViewHostObserver {
               chrome::GoBack(browser, CURRENT_TAB);
           }
 
-          if (isComplete)
+          if (isComplete) {
             [historyOverlay release];
+            [windowController onHistoryOverlayHidden];
+          }
         }];
       return YES;
     }