diff --git a/chrome/android/java/src/org/chromium/chrome/browser/sync/ProfileSyncService.java b/chrome/android/java/src/org/chromium/chrome/browser/sync/ProfileSyncService.java
index 16e6432..33daafb 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/sync/ProfileSyncService.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/sync/ProfileSyncService.java
@@ -153,10 +153,6 @@
         return get().mNativeProfileSyncServiceAndroid;
     }
 
-    public void signOut() {
-        nativeSignOutSync(mNativeProfileSyncServiceAndroid);
-    }
-
     /**
      * Sets the the machine tag used by session sync.
      */
@@ -373,12 +369,6 @@
         nativeSetFirstSetupComplete(mNativeProfileSyncServiceAndroid);
     }
 
-    // TODO(maxbogue): Remove when downstream is updated to use the above.
-    @Deprecated
-    public void setSyncSetupCompleted() {
-        nativeSetFirstSetupComplete(mNativeProfileSyncServiceAndroid);
-    }
-
     public boolean isFirstSetupComplete() {
         return nativeIsFirstSetupComplete(mNativeProfileSyncServiceAndroid);
     }
@@ -455,6 +445,10 @@
         nativeRequestStop(mNativeProfileSyncServiceAndroid);
     }
 
+    public void setSyncAllowedByPlatform(boolean allowed) {
+        nativeSetSyncAllowedByPlatform(mNativeProfileSyncServiceAndroid, allowed);
+    }
+
     /**
      * Flushes the sync directory.
      */
@@ -556,8 +550,9 @@
     private native long nativeInit();
     private native void nativeRequestStart(long nativeProfileSyncServiceAndroid);
     private native void nativeRequestStop(long nativeProfileSyncServiceAndroid);
+    private native void nativeSetSyncAllowedByPlatform(
+            long nativeProfileSyncServiceAndroid, boolean allowed);
     private native void nativeFlushDirectory(long nativeProfileSyncServiceAndroid);
-    private native void nativeSignOutSync(long nativeProfileSyncServiceAndroid);
     private native void nativeSetSyncSessionsId(long nativeProfileSyncServiceAndroid, String tag);
     private native int nativeGetAuthError(long nativeProfileSyncServiceAndroid);
     private native int nativeGetProtocolErrorClientAction(long nativeProfileSyncServiceAndroid);
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/sync/SyncController.java b/chrome/android/java/src/org/chromium/chrome/browser/sync/SyncController.java
index b09e101..9e28c6f 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/sync/SyncController.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/sync/SyncController.java
@@ -146,6 +146,13 @@
      * Updates sync to reflect the state of the Android sync settings.
      */
     private void updateSyncStateFromAndroid() {
+        // Note: |isChromeSyncEnabled| maps to SyncRequested, and
+        // |isMasterSyncEnabled| maps to *both* SyncRequested and
+        // SyncAllowedByPlatform.
+        // TODO(crbug.com/867901): Don't mix these two concepts.
+
+        mProfileSyncService.setSyncAllowedByPlatform(AndroidSyncSettings.isMasterSyncEnabled());
+
         boolean isSyncEnabled = AndroidSyncSettings.isSyncEnabled();
         if (isSyncEnabled == mProfileSyncService.isSyncRequested()) return;
         if (isSyncEnabled) {
diff --git a/chrome/browser/sync/profile_sync_service_android.cc b/chrome/browser/sync/profile_sync_service_android.cc
index e93f595e..653d86b 100644
--- a/chrome/browser/sync/profile_sync_service_android.cc
+++ b/chrome/browser/sync/profile_sync_service_android.cc
@@ -109,9 +109,6 @@
 bool ProfileSyncServiceAndroid::Init() {
   if (sync_service_) {
     sync_service_->AddObserver(this);
-    sync_service_->SetPlatformSyncAllowedProvider(
-        base::Bind(&ProfileSyncServiceAndroid::IsSyncAllowedByAndroid,
-                   base::Unretained(this)));
     return true;
   } else {
     return false;
@@ -121,8 +118,6 @@
 ProfileSyncServiceAndroid::~ProfileSyncServiceAndroid() {
   if (sync_service_) {
     sync_service_->RemoveObserver(this);
-    sync_service_->SetPlatformSyncAllowedProvider(
-        ProfileSyncService::PlatformSyncAllowedProvider());
   }
 }
 
@@ -163,11 +158,11 @@
   sync_service_->RequestStop(ProfileSyncService::KEEP_DATA);
 }
 
-void ProfileSyncServiceAndroid::SignOutSync(JNIEnv* env,
-                                            const JavaParamRef<jobject>&) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  DCHECK(profile_);
-  sync_service_->RequestStop(ProfileSyncService::CLEAR_DATA);
+void ProfileSyncServiceAndroid::SetSyncAllowedByPlatform(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    jboolean allowed) {
+  sync_service_->SetSyncAllowedByPlatform(allowed);
 }
 
 jboolean ProfileSyncServiceAndroid::IsSyncActive(
diff --git a/chrome/browser/sync/profile_sync_service_android.h b/chrome/browser/sync/profile_sync_service_android.h
index 4908b648..a6abe012 100644
--- a/chrome/browser/sync/profile_sync_service_android.h
+++ b/chrome/browser/sync/profile_sync_service_android.h
@@ -53,8 +53,9 @@
                     const base::android::JavaParamRef<jobject>& obj);
   void RequestStop(JNIEnv* env,
                    const base::android::JavaParamRef<jobject>& obj);
-  void SignOutSync(JNIEnv* env,
-                   const base::android::JavaParamRef<jobject>& obj);
+  void SetSyncAllowedByPlatform(JNIEnv* env,
+                                const base::android::JavaParamRef<jobject>& obj,
+                                jboolean allowed);
   jboolean IsSyncActive(JNIEnv* env,
                         const base::android::JavaParamRef<jobject>& obj);
   jboolean IsEngineInitialized(JNIEnv* env,
diff --git a/components/browser_sync/profile_sync_service.cc b/components/browser_sync/profile_sync_service.cc
index f837eaf..a3afd40 100644
--- a/components/browser_sync/profile_sync_service.cc
+++ b/components/browser_sync/profile_sync_service.cc
@@ -197,6 +197,7 @@
           std::make_unique<syncer::HttpBridgeNetworkResources>()),
       start_behavior_(init_params.start_behavior),
       passphrase_prompt_triggered_by_version_(false),
+      sync_allowed_by_platform_(true),
       sync_enabled_weak_factory_(this),
       weak_factory_(this) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
@@ -1526,10 +1527,10 @@
   return engine_ && engine_->IsCryptographerReady(trans);
 }
 
-void ProfileSyncService::SetPlatformSyncAllowedProvider(
-    const PlatformSyncAllowedProvider& platform_sync_allowed_provider) {
+void ProfileSyncService::SetSyncAllowedByPlatform(bool allowed) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  platform_sync_allowed_provider_ = platform_sync_allowed_provider;
+  sync_allowed_by_platform_ = allowed;
+  // TODO(crbug.com/867901): Start or stop Sync as needed here.
 }
 
 void ProfileSyncService::ConfigureDataTypeManager(
@@ -2023,8 +2024,7 @@
 
 bool ProfileSyncService::IsSyncAllowedByPlatform() const {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
-  return platform_sync_allowed_provider_.is_null() ||
-         platform_sync_allowed_provider_.Run();
+  return sync_allowed_by_platform_;
 }
 
 void ProfileSyncService::RequestStop(SyncStopDataFate data_fate) {
diff --git a/components/browser_sync/profile_sync_service.h b/components/browser_sync/profile_sync_service.h
index c49bd41..99062d5 100644
--- a/components/browser_sync/profile_sync_service.h
+++ b/components/browser_sync/profile_sync_service.h
@@ -160,7 +160,6 @@
                            public syncer::UnrecoverableErrorHandler,
                            public GaiaCookieManagerService::Observer {
  public:
-  using PlatformSyncAllowedProvider = base::RepeatingCallback<bool()>;
   using SigninScopedDeviceIdCallback = base::RepeatingCallback<std::string()>;
 
   // NOTE: Used in a UMA histogram, do not reorder etc.
@@ -456,9 +455,8 @@
   // SyncPrefs. Will return the empty string if no bootstrap token exists.
   std::string GetCustomPassphraseKey() const;
 
-  // Set the provider for whether sync is currently allowed by the platform.
-  void SetPlatformSyncAllowedProvider(
-      const PlatformSyncAllowedProvider& platform_sync_allowed_provider);
+  // Set whether sync is currently allowed by the platform.
+  void SetSyncAllowedByPlatform(bool allowed);
 
   // Sometimes we need to wait for tasks on the sync thread in tests.
   base::MessageLoop* GetSyncLoopForTest() const;
@@ -754,9 +752,8 @@
   // IsPassphrasePrompted sync preference.
   bool passphrase_prompt_triggered_by_version_;
 
-  // An object that lets us check whether sync is currently allowed on this
-  // platform.
-  PlatformSyncAllowedProvider platform_sync_allowed_provider_;
+  // Whether sync is currently allowed on this platform.
+  bool sync_allowed_by_platform_;
 
   // This weak factory invalidates its issued pointers when Sync is disabled.
   base::WeakPtrFactory<ProfileSyncService> sync_enabled_weak_factory_;