Android: Reduce visibility of ModuleInstallerImpl

Making ModuleInstallerImpl package-private ensures that callers use the
ModuleInstaller interface instead of depending directly on the
implementation.

Also add stricter parameters and requirements for
ModuleInstaller#initActivity to ensure that SplitCompat#install is
called in the right order (Application first then Activities).

Add /* package */ to classes only used within its package, remove some
redundant public method modifiers in interfaces since all methods in
interfaces are public by default.

Bug: 981084
Change-Id: I4826b2d716fb04fea8b59ed2eff14eb72c843ec7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1761048
Commit-Queue: Peter Wen <wnwen@chromium.org>
Auto-Submit: Peter Wen <wnwen@chromium.org>
Reviewed-by: Tibor Goldschwendt <tiborg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688265}

components/module_installer/android/java/src-common/org/chromium/components/module_installer/ModuleInstaller.java

@@ -4,7 +4,7 @@
 
 package org.chromium.components.module_installer;
 
-import android.content.Context;
+import android.app.Activity;
 
 import org.chromium.base.VisibleForTesting;
 
@@ -32,8 +32,9 @@ public interface ModuleInstaller {
      *
      * For details, see:
      * https://developer.android.com/reference/com/google/android/play/core/splitcompat/SplitCompat.html#install(android.content.Context)
+     * @param activity The Activity for which SplitCompat will be run.
      */
-    default void initActivity(Context context) {}
+    default void initActivity(Activity activity) {}
 
     /**
      * Records via UMA all modules that have been requested and are currently installed. The intent

components/module_installer/android/java/src-common/org/chromium/components/module_installer/ModuleInterface.java

@@ -17,7 +17,7 @@ import java.lang.annotation.Target;
 @Retention(RetentionPolicy.SOURCE)
 public @interface ModuleInterface {
     /** The name of the module. */
-    public String module();
+    String module();
     /** The fully qualified name of the module's interface implementation. */
-    public String impl();
+    String impl();
 }

components/module_installer/android/java/src-common/org/chromium/components/module_installer/observers/ObserverStrategy.java

@@ -11,8 +11,8 @@ import org.chromium.components.module_installer.ModuleInstaller;
 import java.util.List;
 
 /** Interface outlining the necessary strategy to load activities and install modules. */
-interface ObserverStrategy {
-    public ModuleInstaller getModuleInstaller();
-    public List<Activity> getRunningActivities();
-    public int getStateForActivity(Activity activity);
+/* package */ interface ObserverStrategy {
+    ModuleInstaller getModuleInstaller();
+    List<Activity> getRunningActivities();
+    int getStateForActivity(Activity activity);
 }
\ No newline at end of file

components/module_installer/android/java/src-common/org/chromium/components/module_installer/observers/ObserverStrategyImpl.java

@@ -12,7 +12,7 @@ import org.chromium.components.module_installer.ModuleInstaller;
 import java.util.List;
 
 /** Strategy utilizing ModuleInstaller and ApplicationStatus. */
-class ObserverStrategyImpl implements ObserverStrategy {
+/* package */ class ObserverStrategyImpl implements ObserverStrategy {
     @Override
     public ModuleInstaller getModuleInstaller() {
         return ModuleInstaller.getInstance();

components/module_installer/android/java/src-impl/org/chromium/components/module_installer/ModuleInstallerImpl.java

@@ -4,6 +4,7 @@
 
 package org.chromium.components.module_installer;
 
+import android.app.Activity;
 import android.content.Context;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager.NameNotFoundException;
@@ -33,7 +34,7 @@ import java.util.TreeSet;
 
 /** Installs dynamic feature modules (DFMs). */
 @MainDex
-public class ModuleInstallerImpl implements ModuleInstaller {
+/* package */ class ModuleInstallerImpl implements ModuleInstaller {
     /** Command line switch for activating the fake backend.  */
     private static final String FAKE_FEATURE_MODULE_INSTALL = "fake-feature-module-install";
     private static ModuleInstaller sInstance = new ModuleInstallerImpl();
@@ -65,8 +66,11 @@ public class ModuleInstallerImpl implements ModuleInstaller {
     }
 
     @Override
-    public void initActivity(Context context) {
-        SplitCompat.install(context);
+    public void initActivity(Activity activity) {
+        // SplitCompat#install should always be run for the application first before it is run for
+        // any activities.
+        init();
+        SplitCompat.install(activity);
     }
 
     @Override

components/module_installer/android/java/src-stub/org/chromium/components/module_installer/ModuleInstallerImpl.java

@@ -8,7 +8,7 @@ import org.chromium.base.annotations.MainDex;
 
 /** Dummy fallback of ModuleInstaller for APK builds. */
 @MainDex
-public class ModuleInstallerImpl implements ModuleInstaller {
+/* package */ class ModuleInstallerImpl implements ModuleInstaller {
     /** A valid singleton instance is necessary for tests to swap it out. */
     private static ModuleInstaller sInstance = new ModuleInstallerImpl();