DevTools: expose session to handlers.

content/browser/devtools/protocol/security_handler.h

Index: content/browser/devtools/protocol/security_handler.h
diff --git a/content/browser/devtools/protocol/security_handler.h b/content/browser/devtools/protocol/security_handler.h
index 2d32c687a40374a5df7980595827ee2711f067d6..136811a58f61e0ad2a05877aac12cd1ffeb66681 100644
--- a/content/browser/devtools/protocol/security_handler.h
+++ b/content/browser/devtools/protocol/security_handler.h
@@ -12,6 +12,7 @@
 
 namespace content {
 
+class DevToolsAgentHostImpl;
 class RenderFrameHostImpl;
 
 namespace protocol {
@@ -26,6 +27,8 @@ class SecurityHandler : public DevToolsDomainHandler,
   void Wire(UberDispatcher* dispatcher) override;
   void SetRenderFrameHost(RenderFrameHostImpl* host) override;
 
+  static SecurityHandler* FromAgentHost(DevToolsAgentHostImpl* host);
+
   Response Enable() override;
   Response Disable() override;
   Response ShowCertificateViewer() override;