Open ChromeOS clock settings on the UI thread instead of File.

chrome/browser/interstitials/chrome_controller_client.cc

Index: chrome/browser/interstitials/chrome_controller_client.cc
diff --git a/chrome/browser/interstitials/chrome_controller_client.cc b/chrome/browser/interstitials/chrome_controller_client.cc
index 6f6e30f26488e3aef27b92e67a49cc9ef4c8a3c2..abab48a23504ad65f2b0228d8e60df98285b30aa 100644
--- a/chrome/browser/interstitials/chrome_controller_client.cc
+++ b/chrome/browser/interstitials/chrome_controller_client.cc
@@ -42,24 +42,17 @@ using content::Referrer;
 
 namespace {
 
-void LaunchDateAndTimeSettingsOnFile() {
+void LaunchDateAndTimeSettingsOnFileThread() {
   DCHECK_CURRENTLY_ON(content::BrowserThread::FILE);
 // The code for each OS is completely separate, in order to avoid bugs like
-// https://crbug.com/430877 .
+// https://crbug.com/430877 . ChromeOS is handled on the UI thread.
 #if defined(OS_ANDROID)
   chrome::android::OpenDateAndTimeSettings();

[estark, 2016/10/31 19:02:49]

I wonder if this should be on the UI thread as well. I can't figure out if
sending an intent is a blocking operation or not... do you know?

[meacer, 2016/10/31 21:38:22]

Yeah, I was wondering the same thing. 

I don't know about this specific intent, but there is another one in that file
called SendMail. SendMail is called from the UI thread:
https://cs.chromium.org/chromium/src/chrome/browser/ui/webui/net_export_ui.cc...

I can't tell which one is the correct one. How about I land this and keep the
bug open to investigate?

 
-#elif defined(OS_CHROMEOS)
-  std::string sub_page =
-      std::string(chrome::kSearchSubPage) + "#" +
-      l10n_util::GetStringUTF8(IDS_OPTIONS_SETTINGS_SECTION_TITLE_DATETIME);
-  chrome::ShowSettingsSubPageForProfile(ProfileManager::GetActiveUserProfile(),
-                                        sub_page);
-
 #elif defined(OS_LINUX)
   struct ClockCommand {
-    const char* pathname;
-    const char* argument;
+    const char* const pathname;
+    const char* const argument;
   };
   static const ClockCommand kClockCommands[] = {
       // Unity
@@ -150,9 +143,19 @@ bool ChromeControllerClient::CanLaunchDateAndTimeSettings() {
 }
 
 void ChromeControllerClient::LaunchDateAndTimeSettings() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+
+#if defined(OS_CHROMEOS)
+  const std::string sub_page =
+      std::string(chrome::kSearchSubPage) + "#" +
+      l10n_util::GetStringUTF8(IDS_OPTIONS_SETTINGS_SECTION_TITLE_DATETIME);
+  chrome::ShowSettingsSubPageForProfile(ProfileManager::GetActiveUserProfile(),
+                                        sub_page);
+#else
   content::BrowserThread::PostTask(
       content::BrowserThread::FILE, FROM_HERE,
-      base::Bind(&LaunchDateAndTimeSettingsOnFile));
+      base::Bind(&LaunchDateAndTimeSettingsOnFileThread));
+#endif
 }
 
 void ChromeControllerClient::GoBack() {