Adds methods for Cast support to ios::ChromeBrowserProvider.

ios/public/provider/chrome/browser/chrome_browser_provider.h

Index: ios/public/provider/chrome/browser/chrome_browser_provider.h
diff --git a/ios/public/provider/chrome/browser/chrome_browser_provider.h b/ios/public/provider/chrome/browser/chrome_browser_provider.h
index a841ea04d24a6c64dcece8a1e27326dc0f71f5bf..544b1ebf2fbcec9a067e191129ef767b5ba4a4ab 100644
--- a/ios/public/provider/chrome/browser/chrome_browser_provider.h
+++ b/ios/public/provider/chrome/browser/chrome_browser_provider.h
@@ -32,6 +32,10 @@ namespace net {
 class URLRequestContextGetter;
 }
 
+namespace web {
+class WebState;
+}
+
 namespace sync_sessions {
 class SyncedWindowDelegatesGetter;
 }
@@ -119,6 +123,17 @@ class ChromeBrowserProvider {
   // ratings prompts are not supported by the provider.
   virtual id<AppRatingPrompt> CreateAppRatingPrompt() const NS_RETURNS_RETAINED;
 
+  // Initializes the cast service.  Should be called soon after the given
+  // |tab_model| is created.
+  // TODO(rohitrao): Change from |id| to |TabModel*| once TabModel is moved into
+  // the Chromium tree.
+  virtual void InitializeCastService(id tab_model) const;

[Olivier, 2016/10/06 09:26:45]

The name suggests that this will be called only once, and not once per
tab_model.

[rohitrao (ping after 24h), 2016/10/06 12:07:42]

Looking at the callsites, this is only ever called once.

I could rename the argument to |main_tab_model|, to try and make it clearer
(because we only ever create one main tab model).

+
+  // Adds Cast Sender API support to the given |web_state|, if it is supported
+  // by this embedder.
+  virtual void AddCastAPISupportToWebState(web::WebState* web_state,
+                                           NSString* tab_id) const;
+
   // Returns whether safe browsing is enabled. See the comment on
   // metrics_services_manager_client.h for details on |on_update_callback|.
   virtual bool IsSafeBrowsingEnabled(const base::Closure& on_update_callback);