[CrOS] Show system information via Chrome Internal Page

Shows information like CPU usage, Memory status, Zram status.

This patch adds the implementation for the Internal Page backend.
Get system information via Chrome base api, and pass the data to
frontend by calling Javascript function.

Bug: 752002
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: I76c863176270ee61268d22c880b74dafb0958b10
Reviewed-on: https://chromium-review.googlesource.com/625499
Commit-Queue: Zhong-sheng Wu <[email protected]>
Reviewed-by: calamity <[email protected]>
Reviewed-by: Brett Wilson <[email protected]>
Cr-Commit-Position: refs/heads/master@{#499191}
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 34a4701..d6fcf7d 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -765,6 +765,9 @@
 extern const char kSyncSandboxName[];
 extern const char kSyncSandboxDescription[];
 
+extern const char kSysInternalsName[];
+extern const char kSysInternalsDescription[];
+
 extern const char kTabAudioMutingName[];
 extern const char kTabAudioMutingDescription[];