Remove CWV class and move setting User Agent to CWVWebViewConfiguration.

ios/web_view/internal/cwv_web_view_configuration.mm

Index: ios/web_view/internal/cwv_web_view_configuration.mm
diff --git a/ios/web_view/internal/cwv_web_view_configuration.mm b/ios/web_view/internal/cwv_web_view_configuration.mm
index d8916d719da520424576cd898b40c9e11e064559..c70240c32586a804763e1bcb21bf551de9c3f2c1 100644
--- a/ios/web_view/internal/cwv_web_view_configuration.mm
+++ b/ios/web_view/internal/cwv_web_view_configuration.mm
@@ -5,9 +5,12 @@
 #import "ios/web_view/public/cwv_web_view_configuration.h"
 #import "ios/web_view/internal/cwv_web_view_configuration_internal.h"
 
+#include "base/memory/ptr_util.h"
+#include "ios/web/public/app/web_main.h"
 #import "ios/web_view/internal/cwv_user_content_controller_internal.h"
 #import "ios/web_view/internal/web_view_browser_state.h"
 #import "ios/web_view/internal/web_view_web_client.h"
+#import "ios/web_view/internal/web_view_web_main_delegate.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
@@ -30,9 +33,8 @@
   static dispatch_once_t once;
   static CWVWebViewConfiguration* configuration;
   dispatch_once(&once, ^{
-    ios_web_view::WebViewWebClient* client =
-        static_cast<ios_web_view::WebViewWebClient*>(web::GetWebClient());
-    configuration = [[self alloc] initWithBrowserState:client->browser_state()];
+    configuration =
+        [[self alloc] initWithBrowserState:[self webClient]->browser_state()];
   });
   return configuration;
 }
@@ -41,14 +43,26 @@
   static dispatch_once_t once;
   static CWVWebViewConfiguration* configuration;
   dispatch_once(&once, ^{
-    ios_web_view::WebViewWebClient* client =
-        static_cast<ios_web_view::WebViewWebClient*>(web::GetWebClient());
     configuration = [[self alloc]
-        initWithBrowserState:client->off_the_record_browser_state()];
+        initWithBrowserState:[self webClient]->off_the_record_browser_state()];
   });
   return configuration;
 }
 
++ (ios_web_view::WebViewWebClient*)webClient {

[Eugene But (OOO till 7-30), 2017/04/08 00:34:36]

This whole method looks awkward, and I think that's because of the ownership
problems. How about this?:
 - Make WebViewConfiguration own BrowserState, so Configuration does not depend
on WebClient
 - Make WebClient variable static and initialize inside -[CWVWebView initialize]
 - Move WebViewWebMainDelegate, and WebMainParams creation to -[CWVWebView
initialize]
  

[michaeldo, 2017/04/11 17:07:48]

I was able to fix ownership of BrowserState. WebClient lives in the
configuration object because it is allocated first. PTAL.

+  static std::unique_ptr<ios_web_view::WebViewWebMainDelegate> webMainDelegate;
+  static std::unique_ptr<web::WebMain> webMain;
+
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    webMainDelegate = base::MakeUnique<ios_web_view::WebViewWebMainDelegate>();
+    web::WebMainParams params(webMainDelegate.get());
+    webMain = base::MakeUnique<web::WebMain>(params);
+  });
+
+  return static_cast<ios_web_view::WebViewWebClient*>(web::GetWebClient());

[Eugene But (OOO till 7-30), 2017/04/08 00:49:57]

After giving some thoughts, I this we can avoid casting like this:
namespace ios_web_view {
WebViewWebClient* GetWebClient() {
  static WebViewWebClient* web_client;
  web::SetWebClient(&web_client);
  return &web_client;
}
}
And then ios/web_view should only call ios_web_view::GetWebClient() instead of
web::GetWebClient().

WDYT?

[michaeldo, 2017/04/11 17:07:48]

I was able to get rid of the cast by moving webClient static ref to this class
and return correct type directly.

+}
+
 - (instancetype)initWithBrowserState:
     (ios_web_view::WebViewBrowserState*)browserState {
   self = [super init];