Add browser test for CustomizationWallpaperDownloader.

net/url_request/test_url_fetcher_factory.cc

Index: net/url_request/test_url_fetcher_factory.cc
diff --git a/net/url_request/test_url_fetcher_factory.cc b/net/url_request/test_url_fetcher_factory.cc
index d6c66118f32fe8a5e65ae5d6ff4ff8f8bc1d5298..b407027b20c88afa5f650d73f450a912550ed7b1 100644
--- a/net/url_request/test_url_fetcher_factory.cc
+++ b/net/url_request/test_url_fetcher_factory.cc
@@ -8,8 +8,10 @@
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
+#include "base/file_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
+#include "base/threading/thread_restrictions.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
@@ -143,6 +145,12 @@ void TestURLFetcher::SetAutomaticallyRetryOnNetworkChanges(int max_retries) {
 void TestURLFetcher::SaveResponseToFileAtPath(
     const base::FilePath& file_path,
     scoped_refptr<base::SequencedTaskRunner> file_task_runner) {
+  SetResponseFilePath(file_path);
+  // Asynchronous IO is not supported, so file_task_runner is ignored.
+  base::ThreadRestrictions::ScopedAllowIO allow_io;
+  const size_t written_bytes = base::WriteFile(
+      file_path, fake_response_string_.c_str(), fake_response_string_.size());
+  DCHECK_EQ(written_bytes, fake_response_string_.size());
 }
 
 void TestURLFetcher::SaveResponseToTemporaryFile(
@@ -164,6 +172,9 @@ void TestURLFetcher::SaveResponseWithWriter(
     DCHECK_EQ(static_cast<int>(fake_response_string_.size()), response);
     response = response_writer_->Finish(CompletionCallback());
     DCHECK_EQ(OK, response);
+  } else if (fake_response_destination_ == TEMP_FILE) {
+    // File saving is done in SaveResponseToFileAtPath()

[mmenke, 2014/04/29 14:11:40]

I think this comment is confusing.  Suggest something more along the lines of
"SaveResponseToFileAtPath should be called instead in this case" (In
URLFetcherImpl, neither of these functions do any writing, which I think makes
the comment confusing)

[Alexander Alekseev, 2014/04/29 21:42:40]

Done.

+    NOTREACHED();
   } else {
     NOTIMPLEMENTED();
   }