[DevTools] Fix DCHECK related to DevTools agent state callbacks.

BUG=401928

Review URL: https://codereview.chromium.org/453943002

Cr-Commit-Position: refs/heads/master@{#288377}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288377 0039d316-1c4b-4281-b951-d872f2087c98

content/browser/devtools/render_view_devtools_agent_host.cc

@@ -208,6 +208,11 @@ void RenderViewDevToolsAgentHost::OnClientDetached() {
   tracing_handler_->OnClientDetached();
   power_handler_->OnClientDetached();
   ClientDetachedFromRenderer();
+
+  // TODO(kaznacheev): Move this call back to DevToolsManagerImpl when
+  // extensions::ProcessManager no longer relies on this notification.
+  if (!reattaching_)
+    DevToolsManagerImpl::GetInstance()->NotifyObservers(this, false);
 }
 
 void RenderViewDevToolsAgentHost::ClientDetachedFromRenderer() {
@@ -215,11 +220,6 @@ void RenderViewDevToolsAgentHost::ClientDetachedFromRenderer() {
     return;
 
   InnerClientDetachedFromRenderer();
-
-  // TODO(kaznacheev): Move this call back to DevToolsManagerImpl when
-  // extensions::ProcessManager no longer relies on this notification.
-  if (!reattaching_)
-    DevToolsManagerImpl::GetInstance()->NotifyObservers(this, false);
 }
 
 void RenderViewDevToolsAgentHost::InnerClientDetachedFromRenderer() {