Remove CWV class and move setting User Agent to CWVWebViewConfiguration.

ios/web_view/internal/cwv_web_view.mm

Index: ios/web_view/internal/cwv_web_view.mm
diff --git a/ios/web_view/internal/cwv_web_view.mm b/ios/web_view/internal/cwv_web_view.mm
index 08fb4d8dc30b2994005f51fbd5799b2b1efbc42c..1ecfd34f3606029b70cb15aa4563b52685c7a4e2 100644
--- a/ios/web_view/internal/cwv_web_view.mm
+++ b/ios/web_view/internal/cwv_web_view.mm
@@ -25,6 +25,7 @@
 #import "ios/web_view/internal/translate/web_view_translate_client.h"
 #include "ios/web_view/internal/web_view_browser_state.h"
 #import "ios/web_view/internal/web_view_java_script_dialog_presenter.h"
+#import "ios/web_view/internal/web_view_web_client.h"
 #import "ios/web_view/internal/web_view_web_state_policy_decider.h"
 #import "ios/web_view/public/cwv_navigation_delegate.h"
 #import "ios/web_view/public/cwv_ui_delegate.h"
@@ -60,6 +61,11 @@
 @synthesize estimatedProgress = _estimatedProgress;
 @synthesize UIDelegate = _UIDelegate;
 
++ (void)setUserAgentProduct:(NSString*)product {
+  ios_web_view::WebViewWebClient* client = [CWVWebViewConfiguration webClient];
+  client->SetProduct(base::SysNSStringToUTF8(product));
+}
+
 - (instancetype)initWithFrame:(CGRect)frame
                 configuration:(CWVWebViewConfiguration*)configuration {
   self = [super initWithFrame:frame];