[Extensions] Re-enable some AppBackgroundPageApiTest tests.

These tests were disabled for flakiness. They passed 3000
iterations on the bots without flaking. One test fails
consistently on the LaCrOS bot and is disabled for that
build configuration.

Bug: 69215, 108493
Change-Id: Ie93c5949520c39c7b1ec8439f442722795535fd2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2376463
Commit-Queue: David Bertoni <dbertoni@chromium.org>
Reviewed-by: Karan Bhatia <karandeepb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804359}

chrome/browser/extensions/app_background_page_apitest.cc

@@ -11,6 +11,7 @@
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
+#include "build/chromeos_buildflags.h"
 #include "chrome/browser/background/background_contents_service.h"
 #include "chrome/browser/background/background_contents_service_factory.h"
 #include "chrome/browser/background/background_contents_service_observer.h"
@@ -211,8 +212,7 @@ IN_PROC_BROWSER_TEST_F(AppBackgroundPageApiTest, MAYBE_Basic) {
   ASSERT_TRUE(VerifyBackgroundMode(false));
 }
 
-// Crashy, http://crbug.com/69215.
-IN_PROC_BROWSER_TEST_F(AppBackgroundPageApiTest, DISABLED_LacksPermission) {
+IN_PROC_BROWSER_TEST_F(AppBackgroundPageApiTest, LacksPermission) {
   std::string app_manifest = base::StringPrintf(
       "{"
       "  \"name\": \"App\","
@@ -466,8 +466,13 @@ IN_PROC_BROWSER_TEST_F(AppBackgroundPageApiTest, OpenTwoPagesWithManifest) {
   UnloadExtension(extension->id());
 }
 
-// Times out occasionally -- see crbug.com/108493
-IN_PROC_BROWSER_TEST_F(AppBackgroundPageApiTest, DISABLED_OpenPopupFromBGPage) {
+// TODO(https://crbug.com/1124033): Fails on LaCrOS bot.
+#if BUILDFLAG(IS_LACROS)
+#define MAYBE_OpenPopupFromBGPage DISABLED_OpenPopupFromBGPage
+#else
+#define MAYBE_OpenPopupFromBGPage OpenPopupFromBGPage
+#endif
+IN_PROC_BROWSER_TEST_F(AppBackgroundPageApiTest, MAYBE_OpenPopupFromBGPage) {
   std::string app_manifest = base::StringPrintf(
       "{"
       "  \"name\": \"App\","