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}

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

@@ -15,6 +15,8 @@
 #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"
@@ -43,10 +45,6 @@ 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;
 
@@ -177,14 +175,42 @@ 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()));
+}
 
-  // 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.
-  //
+void ArcDefaultAppList::LoadDefaultApps(std::string board_name) {
+  VLOG(1) << "Start loading default apps. Board name is "
+          << (board_name.empty() ? "<unknown>" : board_name);
   std::vector<base::FilePath> sources;
 
   base::FilePath base_path;
@@ -194,16 +220,8 @@ ArcDefaultAppList::ArcDefaultAppList(Profile* profile,
     DCHECK(valid_path);
     const base::FilePath base_arc_path = base_path.Append(kArcDirectory);
     sources.push_back(base_arc_path);
-    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));
-    }
+    if (!board_name.empty())
+      sources.push_back(base_arc_path.Append(board_name));
   } else {
     const bool valid_path =
         base::PathService::Get(chrome::DIR_TEST_DATA, &base_path);
@@ -228,8 +246,6 @@ ArcDefaultAppList::ArcDefaultAppList(Profile* profile,
   }
 }
 
-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

@@ -17,6 +17,7 @@
 #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;
 
@@ -25,7 +26,7 @@ class PrefRegistrySyncable;
 }  // namespace user_prefs
 
 // Contains map of default pre-installed apps and packages.
-class ArcDefaultAppList {
+class ArcDefaultAppList : public arc::ArcSessionManager::Observer {
  public:
   struct AppInfo {
     AppInfo(const std::string& name,
@@ -57,7 +58,7 @@ class ArcDefaultAppList {
   using AppInfoMap = std::map<std::string, std::unique_ptr<AppInfo>>;
 
   ArcDefaultAppList(Profile* profile, base::OnceClosure ready_callback);
-  ~ArcDefaultAppList();
+  ~ArcDefaultAppList() override;
 
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
   static void UseTestAppsDirectory();
@@ -90,6 +91,18 @@ class ArcDefaultAppList {
   }
 
  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.