Instantiate SamlClientProvider instead of injecting it

Injecting the SamlClientProvider led to the SamlCLient to be
unconfigured, which broke the plugin.

The assumed reason is that the SamlWebFilter is being injected, when
loading configured filter classes in core, which is happening before
plugin modules are being installed or other plugin classes were
loaded. Thus, injection didn't work properly.

Change-Id: I71796e669cc6064f955a2aca1497561464a21c50

src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java b/src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java
index 2796b08..044d8db 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/saml/SamlWebFilter.java
@@ -17,16 +17,18 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.Iterators;
 import com.google.common.collect.Sets;
+import com.google.gerrit.common.Nullable;
 import com.google.gerrit.entities.Account;
 import com.google.gerrit.extensions.api.GerritApi;
 import com.google.gerrit.extensions.api.accounts.Accounts;
 import com.google.gerrit.extensions.restapi.RestApiException;
 import com.google.gerrit.extensions.restapi.Url;
 import com.google.gerrit.server.config.AuthConfig;
+import com.google.gerrit.server.config.CanonicalWebUrl;
+import com.google.gerrit.server.config.SitePaths;
 import com.google.gerrit.server.util.ManualRequestContext;
 import com.google.gerrit.server.util.OneOffRequestContext;
 import com.google.inject.Inject;
-import com.google.inject.Provider;
 import com.google.inject.Singleton;
 import java.io.IOException;
 import java.util.Arrays;
@@ -78,18 +80,19 @@
 
   @Inject
   SamlWebFilter(
+      @CanonicalWebUrl @Nullable String canonicalUrl,
+      SitePaths sitePaths,
       AuthConfig auth,
       SamlConfig samlConfig,
       SamlMembership samlMembership,
       GerritApi gApi,
       Accounts accounts,
-      OneOffRequestContext oneOffRequestContext,
-      Provider<SAML2Client> samlClientProvider) {
+      OneOffRequestContext oneOffRequestContext) {
     this.auth = auth;
     this.samlConfig = samlConfig;
     this.samlMembership = samlMembership;
     log.debug("Max Authentication Lifetime: " + samlConfig.getMaxAuthLifetimeAttr());
-    this.saml2Client = samlClientProvider.get();
+    this.saml2Client = new SamlClientProvider(canonicalUrl, sitePaths, samlConfig).get();
 
     this.authHeaders =
         Sets.newHashSet(