[DevTools] Do not create target handler for restricted sessions

Bug: 805224
Change-Id: I08528e44e79d0a097cfe72ab4949dda538efd098
Reviewed-on: https://chromium-review.googlesource.com/988695
Reviewed-by: Pavel Feldman <pfeldman@chromium.org>
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547496}
void RenderFrameDevToolsAgentHost::DestroyOnRenderFrameGone() {
  scoped_refptr<RenderFrameDevToolsAgentHost> protect(this);
  if (IsAttached())
    RevokePolicy();
  ForceDetachAllSessions();
  frame_host_ = nullptr;
  agent_ptr_.reset();
  SetFrameTreeNode(nullptr);
  Release();
}

void RenderFrameDevToolsAgentHost::DestroyOnRenderFrameGone() {
  scoped_refptr<RenderFrameDevToolsAgentHost> protect(this);
  if (IsAttached())
    RevokePolicy();
  ForceDetachAllSessions();
  frame_host_ = nullptr;
  agent_ptr_.reset();
  SetFrameTreeNode(nullptr);
  Release();
}
