Downloads: replace BrowserThread::FILE with task scheduler.

content/browser/download/mhtml_generation_browsertest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <stdint.h>
 #include <memory>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/test/histogram_tester.h"
 #include "base/threading/thread_restrictions.h"
+#include "content/browser/download/download_task_runner.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/common/frame_messages.h"
 #include "content/public/browser/mhtml_extra_parts.h"
 #include "content/public/browser/render_frame_host.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/mhtml_generation_params.h"
 #include "content/public/test/browser_test_utils.h"
 #include "content/public/test/content_browser_test.h"
 #include "content/public/test/content_browser_test_utils.h"
@@ skipping 241 matching lines @@
         render_process_host_(render_process_host) {}
 
  protected:
   ~GenerateMHTMLAndExitRendererMessageFilter() override {}
 
  private:
   bool OnMessageReceived(const IPC::Message& message) override {
     if (message.type() == FrameHostMsg_SerializeAsMHTMLResponse::ID) {
       // After |return false| below, this IPC message will be handled by the
       // product code as illustrated below.  (1), (2), (3) depict points in time
-      // when product code runs on UI and FILE threads.  (X), (Y), (Z) depict
-      // when we want test-injected tasks to run - for the repro, (Z) has to
-      // happen between (1) and (3).  (Y?) and (Z?) depict when test tasks can
-      // theoretically happen and ruin the repro.
+      // when product code runs on UI thread and download sequence.  (X), (Y),
+      // (Z) depict when we want test-injected tasks to run - for the repro, (Z)
+      // has to happen between (1) and (3).  (Y?) and (Z?) depict when test
+      // tasks can theoretically happen and ruin the repro.
       //
-      //     IO thread       UI thread           FILE thread
+      //     IO thread       UI thread         download sequence
       //     ---------       ---------           -----------
       //        |                |                     |
       //    WE ARE HERE          |                     |
       //        |                |                     |
       // after |return false|    |                     |
       //        +--------------->+                     |
       //        |                |                     |
       //        |               (X)                    |
       //        |                |                     |
       //        |                |                    (Y?)
@@ skipping 17 matching lines @@
       //        |                +<--------------------+
       //        |                |                     |
       // (3)    |      MHTMLGenerationManager          |
       //        |      ::OnFileClosed                  |
       //        |                |                     |
       //
       // We hope that (Z) happens between (1) and (3) by doing the following:
       // - From here post TaskX to UI thread.  (X) is guaranteed to happen
       //   before timepoint (1) (because posting of (1) happens after
       //   |return false| / before we post TaskX below).
-      // - From (X) post TaskY to FILE thread.  Because this posting is done
-      //   before (1), we can guarantee that (Y) will happen before (2).
+      // - From (X) post TaskY to downlod sequence.  Because this posting is

[Avi (use Gerrit), 2017/07/21 17:30:08]

typo: download

[Sigurður Ásgeirsson, 2017/07/21 17:38:20]

Done.

+      //   done before (1), we can guarantee that (Y) will happen before (2).
       // - From (Y) post TaskZ to UI thread.  Because this posting is done
       //   before (2), we can guarantee that (Z) will happen before (3).
       // - We cannot really guarantee that (Y) and (Z) happen *after* (1) - i.e.
       //   execution at (Y?) and (Z?) instead is possible.  In practice,
-      //   bouncing off of UI and FILE thread does mean (Z) happens after (1).
+      //   bouncing off of UI and download sequence does mean (Z) happens
+      //   after (1).
       BrowserThread::PostTask(
           BrowserThread::UI, FROM_HERE, base::Bind(
               &GenerateMHTMLAndExitRendererMessageFilter::TaskX,
               base::Unretained(this)));
     }
 
     return false;
   };
 
   void TaskX() {
-    BrowserThread::PostTask(
-        BrowserThread::FILE, FROM_HERE, base::Bind(
-            &GenerateMHTMLAndExitRendererMessageFilter::TaskY,
-            base::Unretained(this)));
+    GetDownloadTaskRunner()->PostTask(
+        FROM_HERE, base::Bind(&GenerateMHTMLAndExitRendererMessageFilter::TaskY,
+                              base::Unretained(this)));
   }
 
   void TaskY() {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE, base::Bind(
             &GenerateMHTMLAndExitRendererMessageFilter::TaskZ,
             base::Unretained(this)));
   }
 
   void TaskZ() {
@@ skipping 371 matching lines @@
     base::ThreadRestrictions::ScopedAllowIO allow_io_for_content_verification;
     ASSERT_TRUE(base::ReadFileToString(path, &mhtml));
   }
 
   // Make sure that both extra data parts made it into the mhtml.
   EXPECT_THAT(mhtml, HasSubstr(kFakeSignalData1));
   EXPECT_THAT(mhtml, HasSubstr(kFakeSignalData2));
 }
 
 }  // namespace content