[WebOTP] Prepare Finch experiment for features::kWebOtpBackend

We plan to ship the new CodeBrowser backend of WebOTP via Finch. This
patch adds necessary code on the client side.

Bug: 1153880
Change-Id: I550ff16d34ec638a0275007b2e1481dec8295115
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2580539
Commit-Queue: Yi Gu <yigu@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Majid Valipour <majidvp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#836321}

content/browser/sms/sms_provider_gms.cc

@@ -9,6 +9,7 @@
 #include "base/android/scoped_java_ref.h"
 #include "base/bind.h"
 #include "base/command_line.h"
+#include "content/public/common/content_features.h"
 #include "content/public/common/content_switches.h"
 
 #include "content/public/android/content_jni_headers/SmsProviderGms_jni.h"
@@ -21,11 +22,15 @@ using base::android::ConvertJavaStringToUTF8;
 namespace content {
 
 SmsProviderGms::SmsProviderGms() {
-  // For backward compat if there is no value provided for switch assume we use
-  // user consent backend.
-  // TODO(majidvp): Change this to be the auto backend once that is fully
-  // launched http://crbug.com/1101050
-  GmsBackend backend = GmsBackend::kUserConsent;
+  // The backend depends on |features::kWebOtpBackendAuto| which is controlled
+  // by both a Finch experiment and chrome://flags. If the feature is enabled,
+  // the "Auto" backend will be used. If not, for backward compatibility we use
+  // the "UserConsent" backend. Note: in case of any conflict between finch and
+  // chrome flags, the latter takes precedence.
+  GmsBackend backend =
+      base::FeatureList::IsEnabled(features::kWebOtpBackendAuto)
+          ? GmsBackend::kAuto
+          : GmsBackend::kUserConsent;
 
   auto switch_value =
       base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(

content/public/common/content_features.cc

@@ -859,10 +859,10 @@ const base::Feature kWebID{"WebID", base::FEATURE_DISABLED_BY_DEFAULT};
 const base::Feature kExperimentalProductivityFeatures{
     "ExperimentalProductivityFeatures", base::FEATURE_DISABLED_BY_DEFAULT};
 
-// When this feature is enabled, the Web OTP API will use the User Consent
-// API to retrieve SMSes from the Android device.
-const base::Feature kWebOtpBackend{"WebOtpBackend",
-                                   base::FEATURE_DISABLED_BY_DEFAULT};
+// Controls which backend is used to retrieve OTP on Android. When disabled
+// we use User Consent API.
+const base::Feature kWebOtpBackendAuto{"WebOtpBackendAuto",
+                                       base::FEATURE_DISABLED_BY_DEFAULT};
 
 // The JavaScript API for payments on the web.
 const base::Feature kWebPayments{"WebPayments",

content/public/common/content_features.h

@@ -193,7 +193,7 @@ CONTENT_EXPORT extern const base::Feature kWebBundlesFromNetwork;
 CONTENT_EXPORT extern const base::Feature kWebContentsOcclusion;
 CONTENT_EXPORT extern const base::Feature kWebGLImageChromium;
 CONTENT_EXPORT extern const base::Feature kWebID;
-CONTENT_EXPORT extern const base::Feature kWebOtpBackend;
+CONTENT_EXPORT extern const base::Feature kWebOtpBackendAuto;
 CONTENT_EXPORT extern const base::Feature kWebPayments;
 CONTENT_EXPORT extern const base::Feature kWebPaymentsMinimalUI;
 CONTENT_EXPORT extern const base::Feature kWebRtcUseGpuMemoryBufferVideoFrames;

testing/variations/fieldtrial_testing_config.json

@@ -8049,6 +8049,22 @@
             ]
         }
     ],
+    "WebOtpBackendAuto": [
+        {
+            "platforms": [
+                "android",
+                "android_weblayer"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "WebOtpBackendAuto"
+                    ]
+                }
+            ]
+        }
+    ],
     "WebProtectConnectors": [
         {
             "platforms": [