Enable resource prefetch from the browser process.

chrome/browser/prefetch/prefetch_browsertest.cc

Index: chrome/browser/prefetch/prefetch_browsertest.cc
diff --git a/chrome/browser/prefetch/prefetch_browsertest.cc b/chrome/browser/prefetch/prefetch_browsertest.cc
index a870be6ffe72a269d4fb5bddb755f2206f67826c..4015169e19c0414f4a3fe4c971813d627c28c8ad 100644
--- a/chrome/browser/prefetch/prefetch_browsertest.cc
+++ b/chrome/browser/prefetch/prefetch_browsertest.cc
@@ -4,15 +4,23 @@
 
 #include "base/command_line.h"
 #include "base/prefs/pref_service.h"
+#include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/pref_names.h"
+#include "chrome/common/prefetch_messages.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "chrome/test/base/ui_test_utils.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/web_contents.h"
 #include "content/public/test/browser_test_utils.h"
+#include "net/url_request/url_request_filter.h"
+#include "net/url_request/url_request_job.h"
+
+using content::BrowserThread;
 
 namespace {
 
@@ -84,6 +92,50 @@ class PrefetchBrowserTestPredictionOffExpOff : public PrefetchBrowserTestBase {
       : PrefetchBrowserTestBase(false, false) {}
 };
 
+// URLRequestJob (and associated handler) which hangs.
+class HangingURLRequestJob : public net::URLRequestJob {
+ public:
+  HangingURLRequestJob(net::URLRequest* request,
+                          net::NetworkDelegate* network_delegate)
+      : net::URLRequestJob(request, network_delegate) {
+  }
+
+  virtual void Start() OVERRIDE {}
+
+ private:
+  virtual ~HangingURLRequestJob() {}
+};
+
+class HangingRequestInterceptor : public net::URLRequestInterceptor {
+ public:
+  explicit HangingRequestInterceptor(base::Closure callback)
+      : callback_(callback) {
+  }
+
+  virtual ~HangingRequestInterceptor() {}
+
+  virtual net::URLRequestJob* MaybeInterceptRequest(
+      net::URLRequest* request,
+      net::NetworkDelegate* network_delegate) const OVERRIDE {
+    if (!callback_.is_null()) {
+      BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, callback_);
+    }
+    return new HangingURLRequestJob(request, network_delegate);
+  }
+
+ private:
+  base::Closure callback_;
+};
+
+void CreateHangingRequestInterceptorOnIO(const GURL& url,
+                                         base::Closure callback) {
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  scoped_ptr<net::URLRequestInterceptor> never_respond_handler(
+      new HangingRequestInterceptor(callback));
+  net::URLRequestFilter::GetInstance()->AddUrlInterceptor(
+      url, never_respond_handler.Pass());
+}
+
 // Privacy option is on, experiment is on.  Prefetch should succeed.
 IN_PROC_BROWSER_TEST_F(PrefetchBrowserTestPredictionOnExpOn, PredOnExpOn) {
   EXPECT_TRUE(RunPrefetchExperiment(true, browser()));
@@ -118,5 +170,20 @@ IN_PROC_BROWSER_TEST_F(PrefetchBrowserTestPredictionOnExpOn, IncognitoTest) {
   EXPECT_TRUE(RunPrefetchExperiment(true, incognito_browser));
 }
 
-}  // namespace
+IN_PROC_BROWSER_TEST_F(PrefetchBrowserTestPredictionOnExpOn,
+                       PrefetchFromBrowser) {
+  const GURL kHangingUrl("http://hanging-url.com");
+  base::RunLoop loop_;
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&CreateHangingRequestInterceptorOnIO,
+                 kHangingUrl,
+                 loop_.QuitClosure()));
+  ui_test_utils::NavigateToURL(browser(), GURL("about:blank"));
+  content::RenderFrameHost* rfh =
+      browser()->tab_strip_model()->GetActiveWebContents()->GetMainFrame();
+  rfh->Send(new PrefetchMsg_Prefetch(rfh->GetRoutingID(), kHangingUrl));
+  loop_.Run();

[jkarlin, 2014/06/16 14:48:29]

What is this test testing exactly?

[tburkard, 2014/06/16 15:02:57]

Done.

added a comment explaining

+}
 
+}  // namespace