Implement request mobile site.

ios/chrome/browser/ui/browser_view_controller.mm

Index: ios/chrome/browser/ui/browser_view_controller.mm
diff --git a/ios/chrome/browser/ui/browser_view_controller.mm b/ios/chrome/browser/ui/browser_view_controller.mm
index 4e535e1707b9fc7381d539b27c44681518c355af..55fd8bd6e2d2b98765a2597056c8187a5543679f 100644
--- a/ios/chrome/browser/ui/browser_view_controller.mm
+++ b/ios/chrome/browser/ui/browser_view_controller.mm
@@ -679,11 +679,9 @@ - (void)tabLoadComplete:(Tab*)tab withSuccess:(BOOL)success;
 // Evaluates Javascript asynchronously using the current page context.
 - (void)openJavascript:(NSString*)javascript;
 
-// Sets the desktop user agent flag and reloads the current page.
-- (void)enableDesktopUserAgent;
-
-// Sets the desktop user agent flag and reloads the current page.
-- (void)enableMobileUserAgent;
+// Reloads the transient item if any, the pending item if a navigation is in
+// progress or the last committed item otherwise with |userAgentType|.
+- (void)reloadWithUserAgentType:(web::UserAgentType)userAgentType;
 
 // Helper methods used by ShareToDelegate methods.
 // Shows an alert with the given title and message id.
@@ -4024,10 +4022,10 @@ - (IBAction)chromeExecuteCommand:(id)sender {
       [[_model currentTab] switchToReaderMode];
       break;
     case IDC_REQUEST_DESKTOP_SITE:
-      [self enableDesktopUserAgent];
+      [self reloadWithUserAgentType:web::UserAgentType::DESKTOP];
       break;
     case IDC_REQUEST_MOBILE_SITE:
-      [self enableMobileUserAgent];
+      [self reloadWithUserAgentType:web::UserAgentType::MOBILE];
       break;
     case IDC_SHOW_TOOLS_MENU: {
       [self showToolsMenuPopup];
@@ -4236,14 +4234,8 @@ - (void)showHelpPage {
                   appendTo:kCurrentTab];
 }
 
-- (void)enableDesktopUserAgent {
-  [[_model currentTab] reloadForDesktopUserAgent];
-}
-
-// TODO(crbug.com/692303): Implement the actual functionality of
-// "Request Mobile Site", and also refactoring the user agent related function
-// names to improve readability.
-- (void)enableMobileUserAgent {
+- (void)reloadWithUserAgentType:(web::UserAgentType)userAgentType {
+  [[_model currentTab] reloadWithUserAgentType:userAgentType];

[kkhorimoto, 2017/04/11 01:09:42]

Let's just call this in-line in the switch statement to avoid the clutter of
adding another 1-line function.

[liaoyuke, 2017/04/11 18:27:20]

Done.

 }
 
 - (void)resetAllWebViews {