Add certificate error handling to devtools.

content/public/browser/web_contents_observer.h

Index: content/public/browser/web_contents_observer.h
diff --git a/content/public/browser/web_contents_observer.h b/content/public/browser/web_contents_observer.h
index 74218f22e802ac54244c7f3ca99d489e54964093..e4eadc8052ee2a9f5587afbcc137b18b4e88972d 100644
--- a/content/public/browser/web_contents_observer.h
+++ b/content/public/browser/web_contents_observer.h
@@ -12,8 +12,10 @@
 #include "base/process/kill.h"
 #include "base/process/process_handle.h"
 #include "content/common/content_export.h"
+#include "content/public/browser/certificate_request_result_type.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/reload_type.h"
+#include "content/public/browser/web_contents.h"
 #include "content/public/common/frame_navigate_params.h"
 #include "content/public/common/resource_type.h"
 #include "ipc/ipc_listener.h"
@@ -298,6 +300,13 @@ class CONTENT_EXPORT WebContentsObserver : public IPC::Listener,
   // This method is invoked when the visible security state of the page changes.
   virtual void DidChangeVisibleSecurityState() {}
 
+  using CertErrorCallback = WebContents::CertErrorCallback;
+  // This method is invoked when there is an internal certificate error.
+  // Return value indicates that this observer will handle the error.
+  virtual bool NotifyCertificateError(int cert_error,
+                                      const GURL& request_url,
+                                      CertErrorCallback callback);
+
   // This method is invoked when content was loaded from an in-memory cache.
   virtual void DidLoadResourceFromMemoryCache(
       const GURL& url,