DevTools: retain DTAH in all the targets to match their life time.

chrome/browser/android/tab_android.cc

Index: chrome/browser/android/tab_android.cc
diff --git a/chrome/browser/android/tab_android.cc b/chrome/browser/android/tab_android.cc
index 45f18987aa13cd35cd78968a8a37d2c2116ee9b2..e41f85a35b8afcf87601055cc0c50bc82406c783 100644
--- a/chrome/browser/android/tab_android.cc
+++ b/chrome/browser/android/tab_android.cc
@@ -65,6 +65,7 @@
 #include "components/url_formatter/url_fixer.h"
 #include "content/public/browser/android/compositor.h"
 #include "content/public/browser/browser_thread.h"
+#include "content/public/browser/devtools_agent_host.h"
 #include "content/public/browser/interstitial_page.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/notification_service.h"
@@ -797,6 +798,15 @@ void TabAndroid::AttachToTabContentManager(
     tab_content_manager_->AttachLiveLayer(GetAndroidId(), GetContentLayer());
 }
 
+scoped_refptr<content::DevToolsAgentHost> TabAndroid::GetDevToolsAgentHost() {
+  return devtools_host_;
+}
+
+void TabAndroid::SetDevToolsAgentHost(
+    scoped_refptr<content::DevToolsAgentHost> host) {
+  devtools_host_ = std::move(host);
+}
+
 static void Init(JNIEnv* env, const JavaParamRef<jobject>& obj) {
   TRACE_EVENT0("native", "TabAndroid::Init");
   // This will automatically bind to the Java object and pass ownership there.