Let CRIWVWebView inherit UIView instead of NSObject.

ios/web_view/internal/criwv_web_view_internal.h

Index: ios/web_view/internal/criwv_web_view_internal.h
diff --git a/ios/web_view/internal/criwv_web_view_impl.h b/ios/web_view/internal/criwv_web_view_internal.h
similarity index 67%
rename from ios/web_view/internal/criwv_web_view_impl.h
rename to ios/web_view/internal/criwv_web_view_internal.h
index fbd9170e9ab082c8b473e93215212f296da232d6..a6eebba84c13df0d3d4874eabdffbb7bfac6dda9 100644
--- a/ios/web_view/internal/criwv_web_view_impl.h
+++ b/ios/web_view/internal/criwv_web_view_internal.h
@@ -11,12 +11,11 @@ namespace ios_web_view {
 class CRIWVBrowserState;
 }
 
-@interface CRIWVWebViewImpl : NSObject<CRIWVWebView>
+@interface CRIWVWebView ()
 
-- (instancetype)init NS_UNAVAILABLE;
-
-- (instancetype)initWithBrowserState:
-    (ios_web_view::CRIWVBrowserState*)browserState NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithFrame:(CGRect)frame

[Eugene But (OOO till 7-30), 2017/02/02 20:54:32]

Could you please document that |browserState| can not be null in the comments.

[Hiroshi Ichikawa, 2017/02/03 02:14:57]

Done.

+                 browserState:(ios_web_view::CRIWVBrowserState*)browserState
+    NS_DESIGNATED_INITIALIZER;
 
 @end