Fix NULL pointer usage, it is P1 crash bug.

content/browser/android/download_controller_android_impl.cc

Index: content/browser/android/download_controller_android_impl.cc
diff --git a/content/browser/android/download_controller_android_impl.cc b/content/browser/android/download_controller_android_impl.cc
index 4da0615494ec2c51138a96bec41fa0f0a6484a7d..1e588bce7766fc69adb4a26f38d28c6a159f04d3 100644
--- a/content/browser/android/download_controller_android_impl.cc
+++ b/content/browser/android/download_controller_android_impl.cc
@@ -111,6 +111,10 @@ void DownloadControllerAndroidImpl::PrepareDownloadInfo(
   net::URLRequest* request =
       ResourceDispatcherHostImpl::Get()->GetURLRequest(global_id);
   DCHECK(request) << "Request to download not found.";

[Philippe, 2012/12/17 15:20:06]

Nit: I would remove these DCHECKs now that we are covered by the if statement
below. As we saw this case looks sane although it's rare.

[felipeg, 2012/12/17 15:21:33]

Done.

+  if (!request) {
+    LOG(ERROR) << "Request to download not found.";
+    return;
+  }
 
   DownloadInfoAndroid info_android(request);
 
@@ -140,6 +144,10 @@ void DownloadControllerAndroidImpl::CheckPolicyAndLoadCookies(
   net::URLRequest* request =
       ResourceDispatcherHostImpl::Get()->GetURLRequest(global_id);
   DCHECK(request) << "Request to download not found.";
+  if (!request) {
+    LOG(ERROR) << "Request to download not found.";
+    return;
+  }
 
   if (request->context()->network_delegate()->CanGetCookies(
       *request, cookie_list)) {
@@ -158,6 +166,10 @@ void DownloadControllerAndroidImpl::DoLoadCookies(
   net::URLRequest* request =
       ResourceDispatcherHostImpl::Get()->GetURLRequest(global_id);
   DCHECK(request) << "Request to download not found.";
+  if (!request) {
+    LOG(ERROR) << "Request to download not found.";
+    return;
+  }
 
   request->context()->cookie_store()->GetCookiesWithOptionsAsync(
       info.url, options,