Handle invalid arc prefs gracefully

There is a crash in ArcPackageNameToAppId. Handle the situation
when prefs are invalid and return empty string. Add DCHECK for
profile passed by pointer.

Bug: 1163362
Change-Id: Icb107de221eaa4e75cc5576eee81dcfd72f47be1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2625154Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842738}

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

@@ -10,6 +10,7 @@
 #include <tuple>
 #include <utility>
 
+#include "base/check.h"
 #include "base/containers/contains.h"
 #include "base/json/json_writer.h"
 #include "base/metrics/histogram_macros.h"
@@ -705,8 +706,10 @@ std::string AppIdToArcPackageName(const std::string& app_id, Profile* profile) {
 
 std::string ArcPackageNameToAppId(const std::string& package_name,
                                   Profile* profile) {
+  DCHECK(profile);
   ArcAppListPrefs* arc_prefs = ArcAppListPrefs::Get(profile);
-  return arc_prefs->GetAppIdByPackageName(package_name);
+  return arc_prefs ? arc_prefs->GetAppIdByPackageName(package_name)
+                   : std::string();
 }
 
 void AddAppLaunchObserver(content::BrowserContext* context,

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

@@ -206,7 +206,7 @@ void GetAndroidId(
 std::string AppIdToArcPackageName(const std::string& app_id, Profile* profile);
 
 // Returns the AppID for the specified package_name, which must be the package
-// name of an ARC app.
+// name of an ARC app or an empty string if name not found.
 std::string ArcPackageNameToAppId(const std::string& package_name,
                                   Profile* profile);