feedback_private: Use aliases for SupportedSource enum types

The long namespace paths of SingleLogFileLogSource::SupportedSource and
SingleDebugDaemonLogSource::SupportedSource are hard to read. Create
aliases to make the switch block cases easier to read.

BUG=762965
R=​[email protected]

Change-Id: I100003d5f286f8b2ee71bc4555e6700b2c0404c3
Reviewed-on: https://chromium-review.googlesource.com/656099
Reviewed-by: Ahmed Fakhry <[email protected]>
Commit-Queue: Simon Que <[email protected]>
Cr-Original-Commit-Position: refs/heads/master@{#500997}(cherry picked from commit 9639526)
Reviewed-on: https://chromium-review.googlesource.com/662379
Cr-Commit-Position: refs/branch-heads/3202@{crosswalk-project#223}
Cr-Branched-From: fa6a5d8-refs/heads/master@{#499098}

chrome/browser/extensions/api/feedback_private/chrome_feedback_private_delegate.cc

@@ -107,25 +107,34 @@ ChromeFeedbackPrivateDelegate::CreateSystemLogsFetcher(
 std::unique_ptr<system_logs::SystemLogsSource>
 ChromeFeedbackPrivateDelegate::CreateSingleLogSource(
     api::feedback_private::LogSource source_type) const {
+  using SupportedLogFileSource =
+      system_logs::SingleLogFileLogSource::SupportedSource;
+  using SupportedDebugDaemonSource =
+      system_logs::SingleDebugDaemonLogSource::SupportedSource;
+
   switch (source_type) {
+    // These map to SupportedLogFileSources.
     case api::feedback_private::LOG_SOURCE_MESSAGES:
       return base::MakeUnique<system_logs::SingleLogFileLogSource>(
-          system_logs::SingleLogFileLogSource::SupportedSource::kMessages);
+          SupportedLogFileSource::kMessages);
     case api::feedback_private::LOG_SOURCE_UILATEST:
       return base::MakeUnique<system_logs::SingleLogFileLogSource>(
-          system_logs::SingleLogFileLogSource::SupportedSource::kUiLatest);
-    case api::feedback_private::LOG_SOURCE_DRMMODETEST:
-      return base::MakeUnique<system_logs::SingleDebugDaemonLogSource>(
-          system_logs::SingleDebugDaemonLogSource::SupportedSource::kModetest);
-    case api::feedback_private::LOG_SOURCE_LSUSB:
-      return base::MakeUnique<system_logs::SingleDebugDaemonLogSource>(
-          system_logs::SingleDebugDaemonLogSource::SupportedSource::kLsusb);
+          SupportedLogFileSource::kUiLatest);
     case api::feedback_private::LOG_SOURCE_ATRUSLOG:
       return base::MakeUnique<system_logs::SingleLogFileLogSource>(
-          system_logs::SingleLogFileLogSource::SupportedSource::kAtrusLog);
+          SupportedLogFileSource::kAtrusLog);
     case api::feedback_private::LOG_SOURCE_NETLOG:
       return base::MakeUnique<system_logs::SingleLogFileLogSource>(
-          system_logs::SingleLogFileLogSource::SupportedSource::kNetLog);
+          SupportedLogFileSource::kNetLog);
+
+    // These map to SupportedDebugDaemonSources.
+    case api::feedback_private::LOG_SOURCE_DRMMODETEST:
+      return base::MakeUnique<system_logs::SingleDebugDaemonLogSource>(
+          SupportedDebugDaemonSource::kModetest);
+    case api::feedback_private::LOG_SOURCE_LSUSB:
+      return base::MakeUnique<system_logs::SingleDebugDaemonLogSource>(
+          SupportedDebugDaemonSource::kLsusb);
+
     case api::feedback_private::LOG_SOURCE_NONE:
     default:
       NOTREACHED() << "Unknown log source type.";