chromeos: make specifying --vmodule work with ChromeOS

Chrome for ChromeOS builds calls to initialize logging twice. If --vmodule
is specified this triggers a CHECK in BaseInitLoggingImpl(). Make it so we
don't redirect logging if not on a device.

BUG=none
TEST=none

Change-Id: Iee4170db4b19cbf4a12add02e2497caabdfb3d59
Reviewed-on: https://chromium-review.googlesource.com/1168106Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581751}

chrome/browser/chromeos/logging.cc

@@ -8,6 +8,7 @@
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
+#include "base/sys_info.h"
 #include "base/task/post_task.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/logging_chrome.h"
@@ -46,6 +47,11 @@ void SymlinkSetUp(const base::CommandLine& command_line,
 void RedirectChromeLogging(const base::CommandLine& command_line) {
   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 
+  // Only redirect when on an actual device. To do otherwise conflicts with
+  // --vmodule that developers may want to use.
+  if (!base::SysInfo::IsRunningOnChromeOS())
+    return;
+
   if (chrome_logging_redirected_) {
     // TODO: Support multiple active users. http://crbug.com/230345
     LOG(WARNING) << "NOT redirecting logging for multi-profiles case.";

chrome/browser/chromeos/login/session/user_session_manager.cc

@@ -1070,8 +1070,7 @@ void UserSessionManager::CreateUserSession(const UserContext& user_context,
 
 void UserSessionManager::PreStartSession() {
   // Switch log file as soon as possible.
-  if (base::SysInfo::IsRunningOnChromeOS())
-    logging::RedirectChromeLogging(*base::CommandLine::ForCurrentProcess());
+  logging::RedirectChromeLogging(*base::CommandLine::ForCurrentProcess());
 }
 
 void UserSessionManager::StoreUserContextDataBeforeProfileIsCreated() {