[ios] Add a delegate to WebStateList class.

ios/clean/chrome/browser/model/browser.h

Index: ios/clean/chrome/browser/model/browser.h
diff --git a/ios/clean/chrome/browser/model/browser.h b/ios/clean/chrome/browser/model/browser.h
index 0e5349f84687719f8b6f40daf977806656e4b8e8..d959ff3c4bf9475bc44c33ff253acabfa0be907e 100644
--- a/ios/clean/chrome/browser/model/browser.h
+++ b/ios/clean/chrome/browser/model/browser.h
@@ -5,8 +5,12 @@
 #ifndef IOS_CLEAN_CHROME_BROWSER_MODEL_BROWSER_H_
 #define IOS_CLEAN_CHROME_BROWSER_MODEL_BROWSER_H_
 
+#include <memory>
+
 #include "base/macros.h"
-#include "ios/shared/chrome/browser/tabs/web_state_list.h"
+
+class WebStateList;
+class WebStateListDelegate;
 
 namespace ios {
 class ChromeBrowserState;
@@ -16,17 +20,18 @@ class ChromeBrowserState;
 // UI elements (Tab strip, ...).
 class Browser {
  public:
-  explicit Browser(ios::ChromeBrowserState* browser_state);
+  Browser(ios::ChromeBrowserState* browser_state,
+          WebStateListDelegate* web_state_list_delegate);

[rohitrao (ping after 24h), 2017/03/14 11:51:11]

Why is this owned by the BrowserList and passed into the Browser, instead of
just being created and owned by the Browser?

   ~Browser();
 
-  WebStateList& web_state_list() { return web_state_list_; }
-  const WebStateList& web_state_list() const { return web_state_list_; }
+  WebStateList* web_state_list() { return web_state_list_.get(); }
+  const WebStateList* web_state_list() const { return web_state_list_.get(); }
 
   ios::ChromeBrowserState* browser_state() const { return browser_state_; }
 
  private:
-  WebStateList web_state_list_;
   ios::ChromeBrowserState* browser_state_;
+  std::unique_ptr<WebStateList> web_state_list_;
 
   DISALLOW_COPY_AND_ASSIGN(Browser);
 };