[Autofill Assistant] Change expected base64 encoding to be url-safe.

Bug: b/175132318
Change-Id: I1b4116420dcd441b6ef089ed7f3c56a8f97048d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2582338Reviewed-by: Lukasz Suder <lsuder@chromium.org>
Commit-Queue: Clemens Arbesser <arbesser@google.com>
Cr-Commit-Position: refs/heads/master@{#835300}

chrome/android/features/autofill_assistant/javatests/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantTriggerScriptIntegrationTest.java

@@ -433,7 +433,7 @@ public class AutofillAssistantTriggerScriptIntegrationTest {
                         .build();
         byte[] triggerScriptsResponse = triggerScripts.toByteArray();
         String base64Response = Base64.encodeToString(triggerScriptsResponse, /* offset = */ 0,
-                triggerScriptsResponse.length, Base64.NO_WRAP);
+                triggerScriptsResponse.length, Base64.URL_SAFE | Base64.NO_WRAP);
         Assert.assertEquals(0, base64Response.length() % 4);
         startAutofillAssistantOnTabWithParams(
                 TEST_PAGE_A, Collections.singletonMap("TRIGGER_SCRIPTS_BASE64", base64Response));

chrome/browser/android/autofill_assistant/trigger_script_bridge_android.cc

@@ -6,7 +6,7 @@
 
 #include "base/android/jni_array.h"
 #include "base/android/jni_string.h"
-#include "base/base64.h"
+#include "base/base64url.h"
 #include "chrome/android/features/autofill_assistant/jni_headers/AssistantTriggerScriptBridge_jni.h"
 #include "chrome/browser/android/autofill_assistant/assistant_header_model.h"
 #include "chrome/browser/android/autofill_assistant/ui_controller_android_utils.h"
@@ -54,9 +54,9 @@ void TriggerScriptBridgeAndroid::StartTriggerScript(
   } else if (trigger_context->GetBase64TriggerScriptsResponseProto()
                  .has_value()) {
     std::string response;
-    if (!base::Base64Decode(
+    if (!base::Base64UrlDecode(
             trigger_context->GetBase64TriggerScriptsResponseProto().value(),
-            &response)) {
+            base::Base64UrlDecodePolicy::IGNORE_PADDING, &response)) {
       LOG(ERROR) << "Failed to base64-decode trigger scripts response";
       Metrics::RecordLiteScriptFinished(
           ukm::UkmRecorder::Get(), client->GetWebContents(),