[Chromecast] Moves persistent UMA client ID handling to common code.

chromecast/browser/cast_browser_process.cc

Index: chromecast/browser/cast_browser_process.cc
diff --git a/chromecast/browser/cast_browser_process.cc b/chromecast/browser/cast_browser_process.cc
index d3cfbfa9eade8c148a9905c0155d16a19a4a8533..be83d008a9bddf673229495fc425b97d6d269ee1 100644
--- a/chromecast/browser/cast_browser_process.cc
+++ b/chromecast/browser/cast_browser_process.cc
@@ -36,7 +36,8 @@ CastBrowserProcess* CastBrowserProcess::GetInstance() {
 }
 
 CastBrowserProcess::CastBrowserProcess()
-    : net_log_(nullptr) {
+    : cast_content_browser_client_(nullptr),
+      net_log_(nullptr) {
   DCHECK(!g_instance);
   g_instance = this;
 }
@@ -54,6 +55,12 @@ void CastBrowserProcess::SetBrowserContext(
   browser_context_.swap(browser_context);
 }
 
+void CastBrowserProcess::SetCastContentBrowserClient(
+    CastContentBrowserClient* cast_content_browser_client) {
+  DCHECK(!cast_content_browser_client_);
+  cast_content_browser_client_ = cast_content_browser_client;
+}
+
 void CastBrowserProcess::SetCastService(scoped_ptr<CastService> cast_service) {
   DCHECK(!cast_service_);
   cast_service_.swap(cast_service);