Use UserAgentType for CRWWebController and web view creation utils

https://chromium-review.googlesource.com/c/542962/ was reverted due to
a bug, however, part of the changes are still useful, so restore them
in this CL. And specifically, this CL refactors CRWWebController and
web view creation utils to use UserAgentType.

Bug: 
Change-Id: Iafaca12bd30d1b84b315295ee090e7ee68161bfe
Reviewed-on: https://chromium-review.googlesource.com/545112
Commit-Queue: Yuke Liao <liaoyuke@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#481922}

ios/web/web_state/ui/crw_web_controller.h

@@ -190,11 +190,11 @@ class WebStateImpl;
 // Dismisses the soft keyboard.
 - (void)dismissKeyboard;
 
-// Requires that the next load rebuild the UIWebView. This is expensive, and
-// should be used only in the case where something has changed that UIWebView
+// Requires that the next load rebuild the web view. This is expensive, and
+// should be used only in the case where something has changed that the web view
 // only checks on creation, such that the whole object needs to be rebuilt.
-// TODO(stuartmorgan): Merge this and reinitializeWebViewAndReload:. They are
-// currently subtly different in terms of implementation, but are for
+// TODO(crbug.com/736102): Merge this and reinitializeWebViewAndReload:. They
+// are currently subtly different in terms of implementation, but are for
 // fundamentally the same purpose.
 - (void)requirePageReconstruction;
 

ios/web/web_state/ui/crw_web_controller.mm

@@ -471,8 +471,10 @@ NSError* WKWebViewErrorWithSource(NSError* error, WKWebViewErrorSource source) {
 // Returns YES if the user interacted with the page recently.
 @property(nonatomic, readonly) BOOL userClickedRecently;
 
-// Whether or not desktop user agent is used for the currentItem.
-@property(nonatomic, readonly) BOOL usesDesktopUserAgent;
+// User agent type of the transient item if any, the pending item if a
+// navigation is in progress or the last committed item otherwise.
+// Returns MOBILE, the default type, if navigation manager is nullptr or empty.
+@property(nonatomic, readonly) web::UserAgentType userAgentType;
 
 // Facade for Mojo API.
 @property(nonatomic, readonly) web::MojoFacade* mojoFacade;
@@ -493,10 +495,11 @@ NSError* WKWebViewErrorWithSource(NSError* error, WKWebViewErrorSource source) {
 // loaded.
 @property(nonatomic, readwrite) BOOL userInteractionRegistered;
 
-// Requires page reconstruction if |item| has a non-NONE UserAgentType and it
-// differs from that of |fromItem|.
-- (void)updateDesktopUserAgentForItem:(web::NavigationItem*)item
-                previousUserAgentType:(web::UserAgentType)userAgentType;
+// Requires page reconstruction if |userAgentType| is a non-NONE and it differs
+// from that of |previousUserAgentType|.
+- (void)updateWebViewFromUserAgentType:(web::UserAgentType)userAgentType
+                 previousUserAgentType:
+                     (web::UserAgentType)previousUserAgentType;
 
 // Removes the container view from the hierarchy and resets the ivar.
 - (void)resetContainerView;
@@ -2055,13 +2058,16 @@ registerLoadRequestForURL:(const GURL&)requestURL
   [self clearTransientContentView];
 
   // Update the user agent before attempting the navigation.
+  // TODO(crbug.com/736103): due to the bug, updating the user agent of web view
+  // requires reconstructing the while web view, change the behavior to call
+  // [WKWebView setCustomUserAgent] once the bug is fixed.
   web::NavigationItem* toItem = items[index].get();
   web::NavigationItem* previousItem = sessionController.currentItem;
   web::UserAgentType previousUserAgentType =
       previousItem ? previousItem->GetUserAgentType()
                    : web::UserAgentType::NONE;
-  [self updateDesktopUserAgentForItem:toItem
-                previousUserAgentType:previousUserAgentType];
+  [self updateWebViewFromUserAgentType:toItem->GetUserAgentType()
+                 previousUserAgentType:previousUserAgentType];
 
   BOOL sameDocumentNavigation =
       [sessionController isSameDocumentNavigationBetweenItem:previousItem
@@ -2221,9 +2227,9 @@ registerLoadRequestForURL:(const GURL&)requestURL
   return rendererInitiatedWithoutInteraction || noNavigationItems;
 }
 
-- (BOOL)usesDesktopUserAgent {
+- (web::UserAgentType)userAgentType {
   web::NavigationItem* item = self.currentNavItem;
-  return item && item->GetUserAgentType() == web::UserAgentType::DESKTOP;
+  return item ? item->GetUserAgentType() : web::UserAgentType::MOBILE;
 }
 
 - (web::MojoFacade*)mojoFacade {
@@ -2262,6 +2268,15 @@ registerLoadRequestForURL:(const GURL&)requestURL
   return _passKitDownloader.get();
 }
 
+- (void)updateWebViewFromUserAgentType:(web::UserAgentType)userAgentType
+                 previousUserAgentType:
+                     (web::UserAgentType)previousUserAgentType {
+  if (userAgentType != web::UserAgentType::NONE &&
+      userAgentType != previousUserAgentType) {
+    [self requirePageReconstruction];
+  }
+}
+
 - (void)updateDesktopUserAgentForItem:(web::NavigationItem*)item
                 previousUserAgentType:(web::UserAgentType)userAgentType {
   if (!item)
@@ -3973,7 +3988,7 @@ registerLoadRequestForURL:(const GURL&)requestURL
   // delegate must be specified.
   return web::BuildWKWebView(CGRectZero, config,
                              self.webStateImpl->GetBrowserState(),
-                             self.usesDesktopUserAgent);
+                             self.userAgentType);
 }
 
 - (void)setWebView:(WKWebView*)webView {

ios/web/web_state/web_view_internal_creation_util.h

@@ -8,6 +8,8 @@
 #import <CoreGraphics/CoreGraphics.h>
 #import <WebKit/WebKit.h>
 
+#include "ios/web/public/user_agent.h"
+
 @protocol CRWContextMenuDelegate;
 
 // This file is a collection of functions that vend web views.
@@ -26,7 +28,7 @@ class BrowserState;
 WKWebView* BuildWKWebView(CGRect frame,
                           WKWebViewConfiguration* configuration,
                           BrowserState* browser_state,
-                          BOOL use_desktop_user_agent,
+                          UserAgentType user_agent_type,
                           id<CRWContextMenuDelegate> context_menu_delegate);
 
 // Creates and returns a new WKWebView for displaying regular web content.
@@ -35,7 +37,7 @@ WKWebView* BuildWKWebView(CGRect frame,
 WKWebView* BuildWKWebView(CGRect frame,
                           WKWebViewConfiguration* configuration,
                           BrowserState* browser_state,
-                          BOOL use_desktop_user_agent);
+                          UserAgentType user_agent_type);
 
 // Creates and returns a new WKWebView for displaying regular web content.
 // The preconditions for the creation of a WKWebView are the same as the

ios/web/web_state/web_view_internal_creation_util.mm

@@ -36,7 +36,7 @@ void VerifyWKWebViewCreationPreConditions(
 WKWebView* BuildWKWebView(CGRect frame,
                           WKWebViewConfiguration* configuration,
                           BrowserState* browser_state,
-                          BOOL use_desktop_user_agent,
+                          UserAgentType user_agent_type,
                           id<CRWContextMenuDelegate> context_menu_delegate) {
   VerifyWKWebViewCreationPreConditions(browser_state, configuration);
 
@@ -44,11 +44,11 @@ WKWebView* BuildWKWebView(CGRect frame,
   WKWebView* web_view =
       [[WKWebView alloc] initWithFrame:frame configuration:configuration];
 
-  // Set the user agent.
-  UserAgentType user_agent_type =
-      use_desktop_user_agent ? UserAgentType::DESKTOP : UserAgentType::MOBILE;
-  web_view.customUserAgent = base::SysUTF8ToNSString(
-      web::GetWebClient()->GetUserAgent(user_agent_type));
+  // Set the user agent type.
+  if (user_agent_type != web::UserAgentType::NONE) {
+    web_view.customUserAgent = base::SysUTF8ToNSString(
+        web::GetWebClient()->GetUserAgent(user_agent_type));
+  }
 
   // By default the web view uses a very sluggish scroll speed. Set it to a more
   // reasonable value.
@@ -77,17 +77,16 @@ WKWebView* BuildWKWebView(CGRect frame,
 WKWebView* BuildWKWebView(CGRect frame,
                           WKWebViewConfiguration* configuration,
                           BrowserState* browser_state,
-                          BOOL use_desktop_user_agent) {
-  return BuildWKWebView(frame, configuration, browser_state,
-                        use_desktop_user_agent, nil);
+                          UserAgentType user_agent_type) {
+  return BuildWKWebView(frame, configuration, browser_state, user_agent_type,
+                        nil);
 }
 
 WKWebView* BuildWKWebView(CGRect frame,
                           WKWebViewConfiguration* configuration,
                           BrowserState* browser_state) {
-  BOOL use_desktop_user_agent = NO;
   return BuildWKWebView(frame, configuration, browser_state,
-                        use_desktop_user_agent);
+                        UserAgentType::MOBILE);
 }
 
 }  // namespace web

ios/web/web_view_creation_util.mm

@@ -5,6 +5,7 @@
 #import "ios/web/public/web_view_creation_util.h"
 
 #include "base/logging.h"
+#include "ios/web/public/user_agent.h"
 #import "ios/web/web_state/ui/wk_web_view_configuration_provider.h"
 #import "ios/web/web_state/web_view_internal_creation_util.h"
 
@@ -27,7 +28,8 @@ WKWebView* BuildWKWebViewWithCustomContextMenu(
   WKWebViewConfigurationProvider& config_provider =
       WKWebViewConfigurationProvider::FromBrowserState(browser_state);
   return BuildWKWebView(frame, config_provider.GetWebViewConfiguration(),
-                        browser_state, NO, context_menu_delegate);
+                        browser_state, UserAgentType::MOBILE,
+                        context_menu_delegate);
 }
 
 }  // namespace web