[DevTools] Fix out of process iframes not working on chrome://inspect.

Regressed in recent refactoring of devtools discovery.
Added checks to existing tests.

BUG=627517

Review-Url: https://codereview.chromium.org/2332213010
Cr-Commit-Position: refs/heads/master@{#419030}

chrome/browser/devtools/chrome_devtools_manager_delegate.cc

@@ -49,6 +49,10 @@ void ChromeDevToolsManagerDelegate::Inspect(
     DevToolsWindow::OpenDevToolsWindowForWorker(profile, agent_host);
     return;
   }
+  if (type == content::DevToolsAgentHost::kTypeFrame) {
+    DevToolsWindow::OpenDevToolsWindow(profile, agent_host);
+    return;
+  }
   content::WebContents* web_contents = agent_host->GetWebContents();
   if (web_contents)
     DevToolsWindow::OpenDevToolsWindow(web_contents);

content/browser/devtools/render_frame_devtools_agent_host.cc

@@ -864,8 +864,8 @@ void RenderFrameDevToolsAgentHost::ConnectWebContents(WebContents* wc) {
 }
 
 std::string RenderFrameDevToolsAgentHost::GetParentId() {
-  if (IsChildFrame()) {
-    RenderFrameHostImpl* frame_host = current_->host();
+  if (IsChildFrame() && current_) {
+    RenderFrameHostImpl* frame_host = current_->host()->GetParent();
     while (frame_host && !ShouldCreateDevToolsFor(frame_host))
       frame_host = frame_host->GetParent();
     if (frame_host)

content/browser/devtools/site_per_process_devtools_browsertest.cc

@@ -100,6 +100,9 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessDevToolsBrowserTest,
   EXPECT_EQ(main_url.spec(), list[0]->GetURL().spec());
   EXPECT_EQ(DevToolsAgentHost::kTypePage, list[1]->GetType());
   EXPECT_EQ(cross_site_url.spec(), list[1]->GetURL().spec());
+  EXPECT_EQ(std::string(), list[0]->GetParentId());
+  EXPECT_EQ(list[0]->GetId(), list[1]->GetParentId());
+  EXPECT_NE(list[1]->GetId(), list[0]->GetId());
 
   // Attaching to both agent hosts.
   scoped_refptr<DevToolsAgentHost> child_host = list[1];
@@ -167,6 +170,8 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessDevToolsBrowserTest, AgentHostForFrames) {
   child_frame_agent =
       DevToolsAgentHost::GetOrCreateFor(child->current_frame_host());
   EXPECT_NE(page_agent.get(), child_frame_agent.get());
+  EXPECT_EQ(child_frame_agent->GetParentId(), page_agent->GetId());
+  EXPECT_NE(child_frame_agent->GetId(), page_agent->GetId());
 }
 
 IN_PROC_BROWSER_TEST_F(SitePerProcessDevToolsBrowserTest,
@@ -194,6 +199,8 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessDevToolsBrowserTest,
   scoped_refptr<DevToolsAgentHost> main_frame_agent =
       DevToolsAgentHost::GetOrCreateFor(root->current_frame_host());
   EXPECT_NE(main_frame_agent.get(), child_frame_agent.get());
+  EXPECT_EQ(child_frame_agent->GetParentId(), main_frame_agent->GetId());
+  EXPECT_NE(child_frame_agent->GetId(), main_frame_agent->GetId());
 
   // Agent for web contents should be the the main frame's one.
   scoped_refptr<DevToolsAgentHost> page_agent =