Why this CL triggers an OilPan crash.

third_party/WebKit/public/web/WebView.h

 /*
  * Copyright (C) 2009, 2010, 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 100 matching lines @@
   using WebWidget::WillCloseLayerTreeView;
   using WebWidget::DidAcquirePointerLock;
   using WebWidget::DidNotAcquirePointerLock;
   using WebWidget::DidLosePointerLock;
   using WebWidget::BackgroundColor;
   using WebWidget::GetPagePopup;
   using WebWidget::UpdateBrowserControlsState;
 
   // Initialization ------------------------------------------------------
 
+  // Special value that can be passed as |browsing_instance_id| argument to
+  // WebView::Create method.  This value designates a view that should not be
+  // related to any other view (example of such a view would be a print-preview
+  // page that adds print header and footer on top of actual web contents).
+  static const int kUnknownBrowsingInstance = -1;
+
   // Creates a WebView that is NOT yet initialized. You will need to
   // call setMainFrame to finish the initialization. It is valid
   // to pass a null client pointer. The WebPageVisibilityState defines the
   // initial visibility of the page.
-  BLINK_EXPORT static WebView* Create(WebViewClient*, WebPageVisibilityState);
+  BLINK_EXPORT static WebView* Create(
+      WebViewClient*,
+      WebPageVisibilityState,
+      int browsing_instance_id = kUnknownBrowsingInstance);
 
   // After creating a WebView, you should immediately call this method.
   // You can optionally modify the settings before calling this method.
   // This WebFrame will receive events for the main frame and must not
   // be null.
   // TODO(mustaq): The non-null param should be a reference.
   virtual void SetMainFrame(WebFrame*) = 0;
 
   // Initializes the various client interfaces.
   virtual void SetCredentialManagerClient(WebCredentialManagerClient*) = 0;
@@ skipping 360 matching lines @@
   // completed.
   WebWidget* GetWidget() { return this; }
 
  protected:
   ~WebView() {}
 };
 
 }  // namespace blink
 
 #endif