Update the ICU's default timezone in render

content/renderer/render_thread_impl.cc

Index: content/renderer/render_thread_impl.cc
diff --git a/content/renderer/render_thread_impl.cc b/content/renderer/render_thread_impl.cc
index 3d713e06ac3cd17331275ad4d832264e3a09c043..3a87450e835546cc2121e5cc648d92e58df48645 100644
--- a/content/renderer/render_thread_impl.cc
+++ b/content/renderer/render_thread_impl.cc
@@ -137,6 +137,7 @@
 #include "third_party/WebKit/public/web/WebScriptController.h"
 #include "third_party/WebKit/public/web/WebSecurityPolicy.h"
 #include "third_party/WebKit/public/web/WebView.h"
+#include "third_party/icu/source/i18n/unicode/timezone.h"
 #include "third_party/skia/include/core/SkGraphics.h"
 #include "ui/base/layout.h"
 #include "ui/base/ui_base_switches.h"
@@ -1695,9 +1696,15 @@ void RenderThreadImpl::OnTempCrashWithData(const GURL& data) {
   CHECK(false);
 }
 
-void RenderThreadImpl::OnUpdateTimezone() {
+void RenderThreadImpl::OnUpdateTimezone(const std::string& zone_id) {
   if (!blink_platform_impl_)
     return;
+  if (!zone_id.empty()) {
+    icu::TimeZone *defaultZone = icu::TimeZone::createTimeZone(
+        icu::UnicodeString::fromUTF8(zone_id));
+    icu::TimeZone::adoptDefault(defaultZone);

[jungshik at Google, 2015/04/10 00:23:44]

adoptDefault() is not thread-safe. If this is called in every thread of
Renderer process, that's a bit problematic (well, we're setting to the same
value, but still it's wasteful to do that multiple times even if there's no
side-effect. TSAN will bark, I guess.)  I wonder if there's a way to call this
only in ONE thread per renderer. 

[jochen (gone - plz use gerrit), 2015/04/10 12:17:24]

can we make it thread safe?

[jungshik at Google, 2015/04/24 22:40:53]

It turned out that I was mistaken about this part. It's called only once per
renderer process afaict. So, I think we don't have to do anything here. 

+    VLOG(0) << "ICU dflt timezone is set to " << zone_id;
+  }
   NotifyTimezoneChange();
 }