Remove request group ID from UA with WKWebView

Without the network stack, there is no need to append a request group
ID to the user agent. This removes it in a minimal way; once the
WKWebView-with-network-stack config is removed it'll be easier to
clean up the cruft.

BUG=None

Review URL: https://codereview.chromium.org/1310763002

Cr-Commit-Position: refs/heads/master@{#345078}

3 files changed, 23 insertions, 10 deletions

diff --git a/ios/web/net/request_group_util.h b/ios/web/net/request_group_util.h
index 525f2d0..071f51f 100644
--- a/ios/web/net/request_group_util.h
+++ b/ios/web/net/request_group_util.h
@@ -30,6 +30,7 @@ NSString* ExtractRequestGroupIDFromUserAgent(NSString* user_agent);
 // Returns a new user agent, which is the result of the encoding of
 // |request_group_id| in |base_user_agent|. The request group ID can be later
 // extracted with ExtractRequestGroupIDFromUserAgent().
+// If request_group_id is nil, returns base_user_agent.
 NSString* AddRequestGroupIDToUserAgent(NSString* base_user_agent,
                                        NSString* request_group_id);
 
diff --git a/ios/web/net/request_group_util.mm b/ios/web/net/request_group_util.mm
index 9a41cef..5aecb10 100644
--- a/ios/web/net/request_group_util.mm
+++ b/ios/web/net/request_group_util.mm
@@ -65,6 +65,8 @@ NSString* ExtractRequestGroupIDFromUserAgent(NSString* user_agent) {
 
 NSString* AddRequestGroupIDToUserAgent(NSString* base_user_agent,
                                        NSString* request_group_id) {
+  if (!request_group_id)
+    return base_user_agent;
   // TODO(blundell): Develop a long-term solution to this problem.
   // crbug.com/329243
   DCHECK([request_group_id length] >= kMinimumIDLength);
diff --git a/ios/web/web_state/ui/crw_wk_web_view_web_controller.mm b/ios/web/web_state/ui/crw_wk_web_view_web_controller.mm
index bee6967..2ece2f9 100644
--- a/ios/web/web_state/ui/crw_wk_web_view_web_controller.mm
+++ b/ios/web/web_state/ui/crw_wk_web_view_web_controller.mm
@@ -147,6 +147,10 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
 // changed.
 @property(nonatomic, readonly) NSDictionary* wkWebViewObservers;
 
+// Returns the string to use as the request group ID in the user agent. Returns
+// nil unless the network stack is enabled.
+@property(nonatomic, readonly) NSString* requestGroupIDForUserAgent;
+
 // Activity indicator group ID for this web controller.
 @property(nonatomic, readonly) NSString* activityIndicatorGroupID;
 
@@ -369,11 +373,11 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
   return _documentURL;
 }
 
+// TODO(stuartmorgan): Remove this method and use the API for WKWebView,
+// making the reset-on-each-load behavior specific to the UIWebView subclass.
 - (void)registerUserAgent {
-  // TODO(stuartmorgan): Rename this method, since it works for both.
-  web::BuildAndRegisterUserAgentForUIWebView(
-      self.webStateImpl->GetRequestGroupID(),
-      [self useDesktopUserAgent]);
+  web::BuildAndRegisterUserAgentForUIWebView([self requestGroupIDForUserAgent],
+                                             [self useDesktopUserAgent]);
 }
 
 // The core.js cannot pass messages back to obj-c  if it is injected
@@ -566,6 +570,14 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
   };
 }
 
+- (NSString*)requestGroupIDForUserAgent {
+#if defined(ENABLE_CHROME_NET_STACK_FOR_WKWEBVIEW)
+  return self.webStateImpl->GetRequestGroupID();
+#else
+  return nil;
+#endif
+}
+
 - (NSString*)activityIndicatorGroupID {
   return [NSString stringWithFormat:
       @"WKWebViewWebController.NetworkActivityIndicatorKey.%@",
@@ -602,12 +614,10 @@ WKWebViewErrorSource WKWebViewErrorSourceFromError(NSError* error) {
 }
 
 - (WKWebView*)createWebViewWithConfiguration:(WKWebViewConfiguration*)config {
-  return [web::CreateWKWebView(
-              CGRectZero,
-              config,
-              self.webStateImpl->GetBrowserState(),
-              self.webStateImpl->GetRequestGroupID(),
-              [self useDesktopUserAgent]) autorelease];
+  return [web::CreateWKWebView(CGRectZero, config,
+                               self.webStateImpl->GetBrowserState(),
+                               [self requestGroupIDForUserAgent],
+                               [self useDesktopUserAgent]) autorelease];
 }
 
 - (void)setWebView:(WKWebView*)webView {