Implement a URLDataSource to load videos from disk for OOBE

This patch implements a URLDataSource that loads oobe video assets from
disk based on the provided chrome URL. It also installs the same for
the oobe web ui.

Bug: 878594
Change-Id: I443144d4e5ab65d313c0e56d8b988a9cb05e6109
Component: Video source, oobe
Reviewed-on: https://chromium-review.googlesource.com/1196145Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Commit-Queue: Malay Keshav <malaykeshav@chromium.org>
Cr-Commit-Position: refs/heads/master@{#587889}

chrome/browser/ui/BUILD.gn

@@ -2089,6 +2089,8 @@ jumbo_split_static_library("ui") {
       "webui/chromeos/system_web_dialog_delegate.h",
       "webui/chromeos/user_image_source.cc",
       "webui/chromeos/user_image_source.h",
+      "webui/chromeos/video_source.cc",
+      "webui/chromeos/video_source.h",
       "webui/extensions/chromeos/kiosk_apps_handler.cc",
       "webui/extensions/chromeos/kiosk_apps_handler.h",
       "webui/help/help_utils_chromeos.cc",

chrome/browser/ui/webui/chromeos/login/oobe_ui.cc

@@ -77,6 +77,7 @@
 #include "chrome/browser/ui/webui/chromeos/login/welcome_screen_handler.h"
 #include "chrome/browser/ui/webui/chromeos/login/wrong_hwid_screen_handler.h"
 #include "chrome/browser/ui/webui/chromeos/user_image_source.h"
+#include "chrome/browser/ui/webui/chromeos/video_source.h"
 #include "chrome/browser/ui/webui/test_files_request_filter.h"
 #include "chrome/browser/ui/webui/theme_source.h"
 #include "chrome/common/chrome_constants.h"
@@ -447,6 +448,9 @@ void OobeUI::ConfigureOobeDisplay() {
   content::WebContents* contents = web_ui()->GetWebContents();
   extensions::TabHelper::CreateForWebContents(contents);
 
+  // // Handler for the oobe video assets which will be shown if available.
+  content::URLDataSource::Add(profile, new chromeos::VideoSource());
+
   if (IsRemoraRequisitioned())
     oobe_display_chooser_ = std::make_unique<OobeDisplayChooser>();
 }

chrome/browser/ui/webui/chromeos/video_source.cc

+// Copyright 2018 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 "chrome/browser/ui/webui/chromeos/video_source.h"
+
+#include <vector>
+
+#include "base/bind.h"
+#include "base/files/file_path.h"
+#include "base/files/file_util.h"
+#include "base/location.h"
+#include "base/memory/ref_counted_memory.h"
+#include "base/sequenced_task_runner.h"
+#include "base/single_thread_task_runner.h"
+#include "base/task/post_task.h"
+#include "base/task/task_scheduler/task_scheduler.h"
+#include "base/task_runner_util.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "chrome/common/url_constants.h"
+#include "net/base/mime_util.h"
+
+namespace chromeos {
+namespace {
+
+const char* kWhitelistedDirectory = "oobe_videos";
+
+bool IsWhitelisted(const std::string& path) {
+  base::FilePath file_path(path);
+  if (file_path.ReferencesParent())
+    return false;
+
+  // Check if the path starts with a whitelisted directory.
+  std::vector<std::string> components;
+  file_path.GetComponents(&components);
+  if (components.empty())
+    return false;
+  return components[0] == kWhitelistedDirectory;
+}
+
+// Callback for user_manager::UserImageLoader.
+void VideoLoaded(
+    const content::URLDataSource::GotDataCallback& got_data_callback,
+    std::unique_ptr<std::string> video_data,
+    bool did_load_file) {
+  if (video_data->size() && did_load_file) {
+    got_data_callback.Run(new base::RefCountedBytes(
+        reinterpret_cast<const unsigned char*>(video_data->data()),
+        video_data->size()));
+  } else {
+    got_data_callback.Run(nullptr);
+  }
+}
+
+}  // namespace
+
+VideoSource::VideoSource() : weak_factory_(this) {
+  task_runner_ = base::CreateSequencedTaskRunnerWithTraits(
+      {base::MayBlock(), base::TaskPriority::USER_VISIBLE,
+       base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN});
+}
+
+VideoSource::~VideoSource() {}
+
+std::string VideoSource::GetSource() const {
+  return chrome::kChromeOSAssetHost;
+}
+
+void VideoSource::StartDataRequest(
+    const std::string& path,
+    const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
+    const content::URLDataSource::GotDataCallback& got_data_callback) {
+  if (!IsWhitelisted(path)) {
+    got_data_callback.Run(nullptr);
+    return;
+  }
+
+  const base::FilePath asset_dir(chrome::kChromeOSAssetPath);
+  const base::FilePath video_path = asset_dir.AppendASCII(path);
+  base::PostTaskWithTraitsAndReplyWithResult(
+      FROM_HERE, {base::MayBlock(), base::TaskPriority::USER_VISIBLE},
+      base::BindOnce(&base::PathExists, video_path),
+      base::BindOnce(&VideoSource::StartDataRequestAfterPathExists,
+                     weak_factory_.GetWeakPtr(), video_path,
+                     got_data_callback));
+}
+
+std::string VideoSource::GetMimeType(const std::string& path) const {
+  std::string mime_type;
+  std::string ext = base::FilePath(path).Extension();
+  if (!ext.empty())
+    net::GetWellKnownMimeTypeFromExtension(ext.substr(1), &mime_type);
+  return mime_type;
+}
+
+void VideoSource::StartDataRequestAfterPathExists(
+    const base::FilePath& video_path,
+    const content::URLDataSource::GotDataCallback& got_data_callback,
+    bool path_exists) {
+  if (path_exists) {
+    auto video_data = std::make_unique<std::string>();
+    std::string* data = video_data.get();
+    base::PostTaskAndReplyWithResult(
+        task_runner_.get(), FROM_HERE,
+        base::BindOnce(&base::ReadFileToString, video_path, data),
+        base::BindOnce(&VideoLoaded, got_data_callback, std::move(video_data)));
+
+  } else {
+    got_data_callback.Run(nullptr);
+  }
+}
+
+}  // namespace chromeos

chrome/browser/ui/webui/chromeos/video_source.h

+// Copyright 2018 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.
+
+#ifndef CHROME_BROWSER_UI_WEBUI_CHROMEOS_VIDEO_SOURCE_H_
+#define CHROME_BROWSER_UI_WEBUI_CHROMEOS_VIDEO_SOURCE_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/scoped_refptr.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/browser/url_data_source.h"
+
+namespace base {
+class FilePath;
+class SequencedTaskRunner;
+}  // namespace base
+
+namespace chromeos {
+
+// Data source that reads videos from the file system.
+// It provides resources from chrome urls of type:
+//   chrome://chromeos-asset/<whitelisted directories>/*.webm
+class VideoSource : public content::URLDataSource {
+ public:
+  VideoSource();
+  ~VideoSource() override;
+
+  // content::URLDataSource:
+  std::string GetSource() const override;
+  void StartDataRequest(
+      const std::string& path,
+      const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
+      const content::URLDataSource::GotDataCallback& got_data_callback)
+      override;
+  std::string GetMimeType(const std::string& path) const override;
+
+ private:
+  // Continuation from StartDataRequest().
+  void StartDataRequestAfterPathExists(
+      const base::FilePath& video_path,
+      const content::URLDataSource::GotDataCallback& got_data_callback,
+      bool path_exists);
+
+  // The background task runner on which file I/O is performed.
+  scoped_refptr<base::SequencedTaskRunner> task_runner_;
+
+  base::WeakPtrFactory<VideoSource> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(VideoSource);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_VIDEO_SOURCE_H_