Why this CL triggers an OilPan crash.

third_party/WebKit/public/web/WebView.h

Index: third_party/WebKit/public/web/WebView.h
diff --git a/third_party/WebKit/public/web/WebView.h b/third_party/WebKit/public/web/WebView.h
index f00b7ac598ef73f780a4f09017106810874ab04d..238d50eb26f5ea4e4c8382cb95c4fd1abca2bc0f 100644
--- a/third_party/WebKit/public/web/WebView.h
+++ b/third_party/WebKit/public/web/WebView.h
@@ -118,11 +118,20 @@ class WebView : protected WebWidget {
 
   // 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.