Remove CWV class and move setting User Agent to CWVWebViewConfiguration.

ios/web_view/internal/web_view_web_client.mm

Index: ios/web_view/internal/web_view_web_client.mm
diff --git a/ios/web_view/internal/web_view_web_client.mm b/ios/web_view/internal/web_view_web_client.mm
index a9c60a05d0ff75b889784b9d4d94aec7c0e5086e..319b5e32e24516c62bcb8a0e38e1b5f5d388891c 100644
--- a/ios/web_view/internal/web_view_web_client.mm
+++ b/ios/web_view/internal/web_view_web_client.mm
@@ -4,10 +4,12 @@
 
 #import "ios/web_view/internal/web_view_web_client.h"
 
+#include "base/strings/sys_string_conversions.h"
 #include "ios/web/public/user_agent.h"
 #include "ios/web_view/internal/web_view_browser_state.h"
 #import "ios/web_view/internal/web_view_early_page_script_provider.h"
 #import "ios/web_view/internal/web_view_web_main_parts.h"
+#include "ios/web_view/public/cwv_web_view.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
@@ -15,8 +17,7 @@
 
 namespace ios_web_view {
 
-WebViewWebClient::WebViewWebClient(const std::string& user_agent_product)
-    : user_agent_product_(user_agent_product), web_main_parts_(nullptr) {}
+WebViewWebClient::WebViewWebClient() : web_main_parts_(nullptr) {}
 
 WebViewWebClient::~WebViewWebClient() = default;
 
@@ -25,16 +26,8 @@ web::WebMainParts* WebViewWebClient::CreateWebMainParts() {
   return web_main_parts_;
 }
 
-WebViewBrowserState* WebViewWebClient::browser_state() const {
-  return web_main_parts_->browser_state();
-}
-
-WebViewBrowserState* WebViewWebClient::off_the_record_browser_state() const {
-  return web_main_parts_->off_the_record_browser_state();
-}
-
 std::string WebViewWebClient::GetProduct() const {
-  return user_agent_product_;
+  return base::SysNSStringToUTF8([CWVWebView userAgentProduct]);
 }
 
 std::string WebViewWebClient::GetUserAgent(web::UserAgentType type) const {