[iOS CBCM] Add unit tests for ReportSchedulerIOS

Adds several unit tests for the ReportSchedulerIOS class. The test cases
ensure an enterprise report is triggered at the correct times, that the
report can be generated successfully, and that error handling is done
correctly, including retrying.

Bug: 1114853
Change-Id: I8e1ca4019067b40b9df40b0cb008983dec4bd9cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2517620
Commit-Queue: Guillaume Jenkins <gujen@google.com>
Reviewed-by: Owen Min <zmin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825428}

ios/chrome/browser/policy/BUILD.gn

@@ -138,6 +138,7 @@ source_set("unit_tests") {
     "reporting/browser_report_generator_ios_unittest.mm",
     "reporting/profile_report_generator_ios_unittest.mm",
     "reporting/report_generator_ios_unittest.mm",
+    "reporting/report_scheduler_ios_unittest.mm",
   ]
   deps = [
     ":policy",
@@ -145,6 +146,8 @@ source_set("unit_tests") {
     ":test_support",
     "//base",
     "//base/test:test_support",
+    "//components/enterprise",
+    "//components/enterprise:test_support",
     "//components/policy/core/browser:test_support",
     "//ios/chrome/browser:chrome_paths",
     "//ios/chrome/browser:pref_names",

ios/chrome/browser/policy/reporting/report_generator_ios_unittest.mm

@@ -63,6 +63,10 @@ class ReportGeneratorIOSTest : public PlatformTest {
                 std::move(browser_state)));
   }
 
+  ReportGeneratorIOSTest(const ReportGeneratorIOSTest&) = delete;
+  ReportGeneratorIOSTest& operator=(const ReportGeneratorIOSTest&) = delete;
+  ~ReportGeneratorIOSTest() override = default;
+
   void InitMockPolicyService() {
     policy_service_ = std::make_unique<policy::MockPolicyService>();
 
@@ -81,9 +85,6 @@ class ReportGeneratorIOSTest : public PlatformTest {
                     base::Value(true), nullptr);
   }
 
-  ReportGeneratorIOSTest(const ReportGeneratorIOSTest&) = delete;
-  ReportGeneratorIOSTest& operator=(const ReportGeneratorIOSTest&) = delete;
-  ~ReportGeneratorIOSTest() override = default;
 
   std::vector<std::unique_ptr<ReportRequest>> GenerateRequests() {
     histogram_tester_ = std::make_unique<base::HistogramTester>();