Fix a bug that counts the C string length wrongly.

BUG=chromium:819444
TEST=Manually tested.

Change-Id: If772cc1efaf8105e92fa6bbfa709ee56110dfe90
Reviewed-on: https://chromium-review.googlesource.com/998514Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Tim Zheng <timzheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#548557}

chrome/browser/ui/app_list/crostini/crostini_util.cc

@@ -40,5 +40,5 @@ std::string CreateCrostiniAppId(const std::string& window_app_id) {
 
 bool IsCrostiniAppId(const std::string& app_id) {
   return strncmp(app_id.c_str(), kCrostiniAppIdPrefix,
-                 sizeof(kCrostiniAppIdPrefix)) == 0;
+                 sizeof(kCrostiniAppIdPrefix) - 1) == 0;
 }

chrome/browser/ui/ash/launcher/crostini_app_window_shelf_controller.cc

@@ -83,7 +83,7 @@ void CrostiniAppWindowShelfController::OnWindowVisibilityChanged(
 
   // Skip handling ARC++ windows.
   if (strncmp(window_app_id->c_str(), kArcAppIdPrefix,
-              sizeof(kArcAppIdPrefix)) == 0)
+              sizeof(kArcAppIdPrefix) - 1) == 0)
     return;
 
   // Skip when this window has been handled. This can happen when the window