[cros] Fix 400 error on gmail.com after sign-in

Throttle redirected requests as well to avoid the racing between
background MergeSession call and tab/xhr loading to google servers.

Bug: 781451
Test: Start up tab of gmail.com loads fine.
Change-Id: Ideb16c8ad8609e0585fe9840f6592fcc2a655360
Reviewed-on: https://chromium-review.googlesource.com/830833
Commit-Queue: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524737}

chrome/browser/chromeos/login/signin/merge_session_navigation_throttle.cc

@@ -45,6 +45,11 @@ MergeSessionNavigationThrottle::WillStartRequest() {
   return content::NavigationThrottle::DEFER;
 }
 
+content::NavigationThrottle::ThrottleCheckResult
+MergeSessionNavigationThrottle::WillRedirectRequest() {
+  return WillStartRequest();
+}
+
 const char* MergeSessionNavigationThrottle::GetNameForLogging() {
   return "MergeSessionNavigationThrottle";
 }

chrome/browser/chromeos/login/signin/merge_session_navigation_throttle.h

@@ -29,6 +29,8 @@ class MergeSessionNavigationThrottle : public content::NavigationThrottle {
 
   // content::NavigationThrottle implementation:
   content::NavigationThrottle::ThrottleCheckResult WillStartRequest() override;
+  content::NavigationThrottle::ThrottleCheckResult WillRedirectRequest()
+      override;
   const char* GetNameForLogging() override;
 
   // MergeSessionLoadPage callback.

chrome/browser/chromeos/login/signin/merge_session_resource_throttle.cc

@@ -52,22 +52,31 @@ MergeSessionResourceThrottle::~MergeSessionResourceThrottle() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 }
 
-void MergeSessionResourceThrottle::WillStartRequest(bool* defer) {
+bool MergeSessionResourceThrottle::MaybeDeferLoading(const GURL& url) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (!merge_session_throttling_utils::ShouldDelayUrl(request_->url()))
-    return;
+  if (!merge_session_throttling_utils::ShouldDelayUrl(url))
+    return false;
 
-  DVLOG(1) << "WillStartRequest: defer " << request_->url();
+  DVLOG(1) << "MergeSessionResourceThrottle: defer " << url;
   const content::ResourceRequestInfo* info =
       content::ResourceRequestInfo::ForRequest(request_);
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::BindOnce(
-          &DelayXHRLoadOnUIThread, info->GetWebContentsGetterForRequest(),
-          request_->url(),
+          &DelayXHRLoadOnUIThread, info->GetWebContentsGetterForRequest(), url,
           base::Bind(&MergeSessionResourceThrottle::OnBlockingPageComplete,
                      weak_factory_.GetWeakPtr())));
-  *defer = true;
+  return true;
+}
+
+void MergeSessionResourceThrottle::WillStartRequest(bool* defer) {
+  *defer = MaybeDeferLoading(request_->url());
+}
+
+void MergeSessionResourceThrottle::WillRedirectRequest(
+    const net::RedirectInfo& redirect_info,
+    bool* defer) {
+  *defer = MaybeDeferLoading(redirect_info.new_url);
 }
 
 const char* MergeSessionResourceThrottle::GetNameForLogging() const {

chrome/browser/chromeos/login/signin/merge_session_resource_throttle.h

@@ -9,6 +9,8 @@
 #include "base/memory/weak_ptr.h"
 #include "content/public/browser/resource_throttle.h"
 
+class GURL;
+
 namespace net {
 class URLRequest;
 }
@@ -19,8 +21,13 @@ class MergeSessionResourceThrottle : public content::ResourceThrottle {
   ~MergeSessionResourceThrottle() override;
 
  private:
+  // Returns true if the resource loading for the given url should be deferred.
+  bool MaybeDeferLoading(const GURL& url);
+
   // content::ResourceThrottle implementation:
   void WillStartRequest(bool* defer) override;
+  void WillRedirectRequest(const net::RedirectInfo& redirect_info,
+                           bool* defer) override;
   const char* GetNameForLogging() const override;
 
   // MergeSessionXHRRequestWaiter callback.