Store NavigationIntext in CRWWKNavigationStates.

ios/web/web_state/ui/crw_wk_navigation_states.h

Index: ios/web/web_state/ui/crw_wk_navigation_states.h
diff --git a/ios/web/web_state/ui/crw_wk_navigation_states.h b/ios/web/web_state/ui/crw_wk_navigation_states.h
index f18713c62c7064ae5efcca1c53ce971a08285083..84eb44c6b570465e58c62d8ea60842084554ac09 100644
--- a/ios/web/web_state/ui/crw_wk_navigation_states.h
+++ b/ios/web/web_state/ui/crw_wk_navigation_states.h
@@ -5,11 +5,15 @@
 #ifndef IOS_WEB_WEB_STATE_UI_CRW_WK_NAVIGATION_STATES_H_
 #define IOS_WEB_WEB_STATE_UI_CRW_WK_NAVIGATION_STATES_H_
 
+#include <memory>
+
 #import <Foundation/Foundation.h>
 #import <WebKit/WebKit.h>
 
 namespace web {
 
+class NavigationContextImpl;
+
 // State of in-flight WKNavigation objects.
 enum class WKNavigationState : int {
   // Navigation does not exist.
@@ -36,8 +40,8 @@ enum class WKNavigationState : int {
 
 }  // namespace web
 
-// Stores states for WKNavigation objects. Allows lookign up for last added
-// navigation object.
+// Stores states and navigation contexts for WKNavigation objects.
+// Allows looking up for last added navigation object.
 @interface CRWWKNavigationStates : NSObject
 
 // Adds a new navigation if it was not added yet. If navigation was already
@@ -53,6 +57,18 @@ enum class WKNavigationState : int {
 // |navigation| is null.
 - (void)removeNavigation:(WKNavigation*)navigation;
 
+// Adds a new navigation if it was not added yet. If navigation was already
+// added then updates context for existing navigation. Updating context does not
+// affect the result of |lastAddedNavigation| method. Passed |navigation| will

[kkhorimoto, 2017/04/25 13:29:55]

Optional: I don't think "Passed" is really necessary here since |navigation|
with the lines unambiguously refers to the passed argument.  Same goes for the
similar comment above.

[Eugene But (OOO till 7-30), 2017/04/25 21:02:58]

Done.

+// be held as weak reference and will not be retained. No-op if |navigation| is
+// null.
+- (void)setContext:(std::unique_ptr<web::NavigationContextImpl>)context
+     forNavigation:(WKNavigation*)navigation;
+
+// Returns context if one was previously associated with given |navigation|.
+// Returns null if |navigation| is null.
+- (web::NavigationContextImpl*)contextForNavigation:(WKNavigation*)navigation;
+
 // WKNavigation which was added the most recently via |setState:forNavigation:|.
 // Updating navigation state via |setState:forNavigation:| does not change the
 // last added navigation. Returns nil if there are no stored navigations.