Revert "arcvm: Get the board name from the generated prop file instead"

This reverts commit 10646707.

Reason for revert: This is a speculative fix. Two Arc changelists
went into this build...
https://ci.chromium.org/p/chromium/builders/ci/linux-chromeos-rel/34691
... and I've already tried reverting the other one, but it didn't
fix the issue. 

If ArcAppDeferredLauncher* tests continue to fail with this revert
then this can be unreverted and the Arc tests need to be disabled.

Original change's description:
> arcvm: Get the board name from the generated prop file instead
> 
> On some boards like nami, CrOS rootfs' build.prop doesn't have the
> complete ro.product.board entry. It's sometimes a template. To always
> get the board name on all boards, ArcDefaultAppList needs to wait
> for ArcSessionManager to generate the board's own build.prop file
> in its stateful partition. This is the same as what arc-setup does
> today.
> 
> This CL also stops special casing ARCVM and does the same for
> ARC too. Also, when calling GetBoardName(), this CL uses
> MayBlock() to make it debug build compatible.
> 
> BUG=b:144199481
> TEST=try, ARCVM still starts
> 
> Change-Id: Ie878d9ffff98ecf3b9dccb837fd6dce1a382a4be
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2026668
> Commit-Queue: Yusuke Sato <yusukes@chromium.org>
> Reviewed-by: Yury Khmel <khmel@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#739250}

TBR=yusukes@chromium.org,khmel@google.com,khmel@chromium.org

Change-Id: I5a75922a9b101aafb1bb03de86826003a41ce599
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: b:144199481
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2044152Reviewed-by: Finnur Thorarinsson <finnur@chromium.org>
Commit-Queue: Finnur Thorarinsson <finnur@chromium.org>
Cr-Commit-Position: refs/heads/master@{#739372}

chrome/browser/ui/app_list/arc/arc_default_app_list.cc

@@ -15,8 +15,6 @@
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
 #include "base/task/post_task.h"
-#include "base/task/task_traits.h"
-#include "base/task_runner.h"
 #include "chrome/browser/chromeos/arc/arc_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/app_list/arc/arc_app_list_prefs.h"
@@ -45,6 +43,10 @@ const base::FilePath::CharType kArcTestDirectory[] =
     FILE_PATH_LITERAL("arc_default_apps");
 const base::FilePath::CharType kArcTestBoardDirectory[] =
     FILE_PATH_LITERAL("arc_board_default_apps");
+const base::FilePath::CharType kBoardDirectory[] =
+    FILE_PATH_LITERAL("/var/cache/arc_default_apps");
+const base::FilePath::CharType kBuildProp[] =
+    FILE_PATH_LITERAL("/usr/share/arcvm/properties/build.prop");
 
 bool use_test_apps_directory = false;
 
@@ -175,42 +177,14 @@ ArcDefaultAppList::ArcDefaultAppList(Profile* profile,
                                      base::OnceClosure ready_callback)
     : profile_(profile), ready_callback_(std::move(ready_callback)) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
-  arc::ArcSessionManager::Get()->AddObserver(this);
-}
-
-ArcDefaultAppList::~ArcDefaultAppList() {
-  auto* manager = arc::ArcSessionManager::Get();
-  if (manager)  // for unit testing
-    manager->RemoveObserver(this);
-}
-
-void ArcDefaultAppList::OnPropertyFilesExpanded(bool result) {
-  if (!result) {
-    // Failed to generate |kGeneratedPropertyFilesPath[Vm]| for whatever reason.
-    // Continue anyway not to stall the launcher initialization. In this case,
-    // ARC[VM] itself won't start, so not being able to get the board name won't
-    // be a huge problem either.
-    VLOG(1) << "Unable to get the board name.";
-    LoadDefaultApps(std::string());
-    return;
-  }
-
-  VLOG(1) << "Getting the board name";
-  const char* source_dir = arc::IsArcVmEnabled()
-                               ? arc::kGeneratedPropertyFilesPathVm
-                               : arc::kGeneratedPropertyFilesPath;
-  base::PostTaskAndReplyWithResult(
-      FROM_HERE,
-      {base::ThreadPool(), base::MayBlock(), base::TaskPriority::USER_VISIBLE},
-      base::BindOnce(&GetBoardName,
-                     base::FilePath(source_dir).Append("build.prop")),
-      base::BindOnce(&ArcDefaultAppList::LoadDefaultApps,
-                     weak_ptr_factory_.GetWeakPtr()));
-}
 
-void ArcDefaultAppList::LoadDefaultApps(std::string board_name) {
-  VLOG(1) << "Start loading default apps. Board name is "
-          << (board_name.empty() ? "<unknown>" : board_name);
+  // Load default apps from two sources.
+  // /usr/share/google-chrome/extensions/arc - contains default apps for all
+  //     boards that share the same image.
+  // /var/cache/arc_default_apps that is link to
+  //     /usr/share/google-chrome/extensions/arc/BOARD_NAME - contains default
+  //     apps for particular current board.
+  //
   std::vector<base::FilePath> sources;
 
   base::FilePath base_path;
@@ -220,8 +194,16 @@ void ArcDefaultAppList::LoadDefaultApps(std::string board_name) {
     DCHECK(valid_path);
     const base::FilePath base_arc_path = base_path.Append(kArcDirectory);
     sources.push_back(base_arc_path);
-    if (!board_name.empty())
-      sources.push_back(base_arc_path.Append(board_name));
+    if (arc::IsArcVmEnabled()) {
+      // ARCVM environment doesn't have the symlink. Get the board name on the
+      // fly instead.
+      // TODO(yusukes): Do the same for ARC and remove the arc-setup code for
+      // creating the symlink.
+      sources.push_back(
+          base_arc_path.Append(GetBoardName(base::FilePath(kBuildProp))));
+    } else {
+      sources.push_back(base::FilePath(kBoardDirectory));
+    }
   } else {
     const bool valid_path =
         base::PathService::Get(chrome::DIR_TEST_DATA, &base_path);
@@ -246,6 +228,8 @@ void ArcDefaultAppList::LoadDefaultApps(std::string board_name) {
   }
 }
 
+ArcDefaultAppList::~ArcDefaultAppList() = default;
+
 void ArcDefaultAppList::OnAppsRead(std::unique_ptr<AppInfoMap> apps) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 

chrome/browser/ui/app_list/arc/arc_default_app_list.h

@@ -17,7 +17,6 @@
 #include "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
-#include "chrome/browser/chromeos/arc/session/arc_session_manager.h"
 
 class Profile;
 
@@ -26,7 +25,7 @@ class PrefRegistrySyncable;
 }  // namespace user_prefs
 
 // Contains map of default pre-installed apps and packages.
-class ArcDefaultAppList : public arc::ArcSessionManager::Observer {
+class ArcDefaultAppList {
  public:
   struct AppInfo {
     AppInfo(const std::string& name,
@@ -58,7 +57,7 @@ class ArcDefaultAppList : public arc::ArcSessionManager::Observer {
   using AppInfoMap = std::map<std::string, std::unique_ptr<AppInfo>>;
 
   ArcDefaultAppList(Profile* profile, base::OnceClosure ready_callback);
-  ~ArcDefaultAppList() override;
+  ~ArcDefaultAppList();
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
   static void UseTestAppsDirectory();
@@ -91,18 +90,6 @@ class ArcDefaultAppList : public arc::ArcSessionManager::Observer {
   }
 
  private:
-  // arc::ArcSessionManager::Observer:
-  void OnPropertyFilesExpanded(bool result) override;
-
-  // Loads default apps from two sources:
-  //
-  // /usr/share/google-chrome/extensions/arc - contains default apps for all
-  //     boards that share the same image.
-  // /usr/share/google-chrome/extensions/arc/<BOARD_NAME> - contains default
-  //     apps for particular current board.
-  //
-  void LoadDefaultApps(std::string board_name);
-
   // Called when default apps are read from the provided source.
   void OnAppsRead(std::unique_ptr<AppInfoMap> apps);
   // Called when default apps from all sources are read.