[Sync] Refactoring of sync integration test checkers to remove boilerplate await methods.

chrome/browser/sync/test/integration/preferences_helper.h

Index: chrome/browser/sync/test/integration/preferences_helper.h
diff --git a/chrome/browser/sync/test/integration/preferences_helper.h b/chrome/browser/sync/test/integration/preferences_helper.h
index aaa5ad882018a5188a6d25299de7c9be3f50f6f6..2a98b9122627ea99eaa8d11cd3a6d15bb495a9e4 100644
--- a/chrome/browser/sync/test/integration/preferences_helper.h
+++ b/chrome/browser/sync/test/integration/preferences_helper.h
@@ -5,13 +5,17 @@
 #ifndef CHROME_BROWSER_SYNC_TEST_INTEGRATION_PREFERENCES_HELPER_H_
 #define CHROME_BROWSER_SYNC_TEST_INTEGRATION_PREFERENCES_HELPER_H_
 
-#include "base/files/file_path.h"
-#include "base/values.h"
-
 #include <stdint.h>
 
+#include <memory>
 #include <string>
+#include <vector>
+
+#include "base/files/file_path.h"
+#include "base/values.h"
+#include "chrome/browser/sync/test/integration/multi_client_status_change_checker.h"
 
+class PrefChangeRegistrar;
 class PrefService;
 
 namespace preferences_helper {
@@ -98,22 +102,62 @@ bool FilePathPrefMatches(const char* pref_name) WARN_UNUSED_RESULT;
 // hasn't been called.
 bool ListPrefMatches(const char* pref_name) WARN_UNUSED_RESULT;
 
-// This is the version of ListPrefMatches that waits for the preference list
-// to match in all profiles. Returns false if this operation times out.
-bool AwaitListPrefMatches(const char* pref_name) WARN_UNUSED_RESULT;
-
-// Blocks the test until the specified pref matches on all relevant clients or
-// a timeout occurs.  Returns false if it returns because of a timeout.
-bool AwaitBooleanPrefMatches(const char* pref_name) WARN_UNUSED_RESULT;
-
-// Blocks the test until the specified pref matches on all relevant clients or
-// a timeout occurs.  Returns false if it returns because of a timeout.
-bool AwaitIntegerPrefMatches(const char* pref_name) WARN_UNUSED_RESULT;
-
-// Blocks the test until the specified pref matches on all relevant clients or
-// a timeout occurs.  Returns false if it returns because of a timeout.
-bool AwaitStringPrefMatches(const char* pref_name) WARN_UNUSED_RESULT;
-
 }  // namespace preferences_helper
 
+// Abstract checker that takes care of registering for preference changes.
+class PrefMatchChecker : public StatusChangeChecker {
+ public:
+  explicit PrefMatchChecker(const char* path);
+  ~PrefMatchChecker() override;
+
+  // StatusChangeChecker implementation.
+  bool IsExitConditionSatisfied() override = 0;
+  std::string GetDebugMessage() const override;
+
+ protected:
+  const char* GetPath() const;
+
+ private:
+  void RegisterPrefListener(PrefService* pref_service);
+
+  std::vector<std::unique_ptr<PrefChangeRegistrar>> pref_change_registrars_;
+  const char* path_;
+};
+
+// Matcher that blocks until the specified list pref matches on all clients.
+class ListPrefMatchChecker : public PrefMatchChecker {
+ public:
+  explicit ListPrefMatchChecker(const char* path);
+
+  // PrefMatchChecker implementation.
+  bool IsExitConditionSatisfied() override;
+};
+
+// Matcher that blocks until the specified boolean pref matches on all clients.
+class BooleanPrefMatchChecker : public PrefMatchChecker {
+ public:
+  explicit BooleanPrefMatchChecker(const char* path);
+
+  // PrefMatchChecker implementation.
+  bool IsExitConditionSatisfied() override;
+};
+
+// Matcher that blocks until the specified integer pref matches on all clients.
+class IntegerPrefMatchChecker : public PrefMatchChecker {
+ public:
+  explicit IntegerPrefMatchChecker(const char* path);
+
+  // PrefMatchChecker implementation.
+  bool IsExitConditionSatisfied() override;
+};
+
+// Matcher that blocks until the specified string pref matches on all clients.
+class StringPrefMatchChecker : public PrefMatchChecker {
+ public:
+  explicit StringPrefMatchChecker(const char* path);
+
+  // PrefMatchChecker implementation.
+  bool IsExitConditionSatisfied() override;
+};
+
 #endif  // CHROME_BROWSER_SYNC_TEST_INTEGRATION_PREFERENCES_HELPER_H_