Fix device_event_log component build, make NonThreadSafe (Take 2)

chrome/browser/chrome_browser_main.cc

Index: chrome/browser/chrome_browser_main.cc
diff --git a/chrome/browser/chrome_browser_main.cc b/chrome/browser/chrome_browser_main.cc
index 94d64620fa0528ce244baa4303e66098e8d07cbb..611ff39f0caaf1a7897e3ae63d780c622f2e77c8 100644
--- a/chrome/browser/chrome_browser_main.cc
+++ b/chrome/browser/chrome_browser_main.cc
@@ -797,14 +797,19 @@ void ChromeBrowserMainParts::ToolkitInitialized() {
 void ChromeBrowserMainParts::PreMainMessageLoopStart() {
   TRACE_EVENT0("startup", "ChromeBrowserMainParts::PreMainMessageLoopStart");
 
-  device_event_log::Initialize(0 /* default max entries */);
-
   for (size_t i = 0; i < chrome_extra_parts_.size(); ++i)
     chrome_extra_parts_[i]->PreMainMessageLoopStart();
 }
 
 void ChromeBrowserMainParts::PostMainMessageLoopStart() {
   TRACE_EVENT0("startup", "ChromeBrowserMainParts::PostMainMessageLoopStart");
+
+  // device_event_log must be initialized after the message loop. Calls to
+  // {DEVICE}_LOG prior to here will only be logged with VLOG. Some
+  // platforms (e.g. chromeos) may have already initialized this.
+  if (!device_event_log::IsInitialized())
+    device_event_log::Initialize(0 /* default max entries */);
+
   for (size_t i = 0; i < chrome_extra_parts_.size(); ++i)
     chrome_extra_parts_[i]->PostMainMessageLoopStart();
 }