Remove redundant DevToolsManager methods and clean up its clients.

chrome/browser/devtools/devtools_adb_bridge.cc

Index: chrome/browser/devtools/devtools_adb_bridge.cc
diff --git a/chrome/browser/devtools/devtools_adb_bridge.cc b/chrome/browser/devtools/devtools_adb_bridge.cc
index eddf865b3f0f7b70a04a481ee63204658393611f..7a38fadd12d5aaec053b8c93b9b02f0ae91a54b3 100644
--- a/chrome/browser/devtools/devtools_adb_bridge.cc
+++ b/chrome/browser/devtools/devtools_adb_bridge.cc
@@ -329,11 +329,8 @@ class AgentHostDelegate : public base::RefCountedThreadSafe<AgentHostDelegate>,
     if (!value || !value->GetAsDictionary(&dvalue))
       return;
 
-    content::DevToolsManager* manager = content::DevToolsManager::GetInstance();
-    content::DevToolsClientHost* client_host =
-        manager->GetDevToolsClientHostFor(proxy_->GetAgentHost());
-    if (client_host)
-      client_host->DispatchOnInspectorFrontend(message);
+    content::DevToolsManager::GetInstance()->
+        DispatchOnInspectorFrontend(proxy_->GetAgentHost(), message);
   }
 
   void OnSocketClosed(int result) {