Remove redundant DevToolsManager methods and clean up its clients.

content/browser/devtools/render_view_devtools_agent_host.cc

Index: content/browser/devtools/render_view_devtools_agent_host.cc
diff --git a/content/browser/devtools/render_view_devtools_agent_host.cc b/content/browser/devtools/render_view_devtools_agent_host.cc
index 3687766c5ea1b797f22dfc48fa232215de13fe5e..f21e1a8ce1eaac5971d610b848af28014942ab59 100644
--- a/content/browser/devtools/render_view_devtools_agent_host.cc
+++ b/content/browser/devtools/render_view_devtools_agent_host.cc
@@ -99,7 +99,7 @@ bool DevToolsAgentHost::IsDebuggerAttached(WebContents* web_contents) {
     RenderViewHost* rvh = (*it)->render_view_host_;
     if (rvh && rvh->GetDelegate() != delegate)
       continue;
-    if (devtools_manager->GetDevToolsClientHostFor(*it))
+    if (devtools_manager->IsAttached(*it))
       return true;
   }
   return false;
@@ -237,7 +237,7 @@ void RenderViewDevToolsAgentHost::NotifyClientDetaching() {
   RenderProcessHost* render_process_host = render_view_host_->GetProcess();
   for (Instances::iterator it = g_instances.Get().begin();
        it != g_instances.Get().end(); ++it) {
-    if (*it == this || !devtools_manager->GetDevToolsClientHostFor(*it))
+    if (*it == this || !devtools_manager->IsAttached(*it))
       continue;
     RenderViewHost* rvh = (*it)->render_view_host();
     if (rvh && rvh->GetProcess() == render_process_host)