[Android WebAPKs] Do not remove task when user presses back in new-style WebAPK

- This CL changes the back button when a user is in a WebAPK from using
Activity#finish() to using Activity#finishAndRemoveTask()
- Activity#finishAndRemoveTask() is still used if the user pressed back
while the splash screen is up because WebApkActivity is still translucent
at this point and Activity#finish() causes an ugly transition when
WebApkActivity is translucent.

BUG=982956

Change-Id: Ie39b2c6902bef2d22e6052a47013f15975fbb611
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1717556
Commit-Queue: Peter Kotwicz <pkotwicz@chromium.org>
Reviewed-by: Pavel Shmakov <pshmakov@chromium.org>
Reviewed-by: Dominick Ng <dominickn@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681846}

chrome/android/java/src/org/chromium/chrome/browser/webapps/SplashController.java

@@ -157,6 +157,10 @@ public class SplashController extends EmptyTabObserver implements InflationObser
         mParentView.addView(mSplashView);
     }
 
+    public boolean isSplashShowing() {
+        return mSplashView != null;
+    }
+
     @VisibleForTesting
     View getSplashScreenForTests() {
         return mSplashView;

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java

@@ -134,7 +134,7 @@ public class WebApkActivity extends WebappActivity {
     protected boolean handleBackPressed() {
         if (super.handleBackPressed()) return true;
 
-        if (getWebappInfo().isSplashProvidedByWebApk()) {
+        if (getWebappInfo().isSplashProvidedByWebApk() && isSplashShowing()) {
             // When the WebAPK provides the splash screen, the splash screen activity is stacked
             // underneath the WebAPK. The splash screen finishes itself in
             // {@link Activity#onResume()}. When finishing the WebApkActivity, there is sometimes a

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappActivity.java

@@ -899,6 +899,10 @@ public class WebappActivity extends SingleTabActivity {
                 getWindowAndroid(), (byte) mWebappInfo.orientation());
     }
 
+    protected boolean isSplashShowing() {
+        return mSplashController.isSplashShowing();
+    }
+
     /**
      * Register an observer to the splashscreen hidden/visible events for this activity.
      */

chrome/android/webapk/shell_apk/AndroidManifest.xml

@@ -51,9 +51,7 @@
         [[#use_new_splash]]
         <activity android:name="org.chromium.webapk.shell_apk.h2o.H2OOpaqueMainActivity"
                   android:theme="@style/SplashTheme"
-                  android:relinquishTaskIdentity="true"
-                  android:excludeFromRecents="true"
-                  android:noHistory="true">
+                  android:relinquishTaskIdentity="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />

chrome/android/webapk/shell_apk/current_version/current_version.gni

@@ -12,4 +12,4 @@
 # //chrome/android/webapk/shell_apk:webapk is changed. This includes
 # Java files, Android resource files and AndroidManifest.xml. Does not affect
 # Chrome.apk
-current_shell_apk_version = 101
+current_shell_apk_version = 102

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/WebApkUtils.java

@@ -5,7 +5,6 @@
 package org.chromium.webapk.shell_apk;
 
 import android.annotation.TargetApi;
-import android.app.Activity;
 import android.app.ActivityManager;
 import android.content.ComponentName;
 import android.content.Context;
@@ -282,14 +281,6 @@ public class WebApkUtils {
                 .setData(Uri.parse("http://"));
     }
 
-    public static void finishAndRemoveTask(Activity activity) {
-        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP) {
-            activity.finishAndRemoveTask();
-        } else {
-            activity.finish();
-        }
-    }
-
     public static String getNotificationChannelName(Context context) {
         return context.getString(R.string.notification_channel_name);
     }

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/h2o/H2OOpaqueMainActivity.java

@@ -35,5 +35,6 @@ public class H2OOpaqueMainActivity extends Activity {
         overridePendingTransition(0, 0);
         H2OLauncher.copyIntentExtrasAndLaunch(
                 appContext, getIntent(), null, new ComponentName(appContext, SplashActivity.class));
+        finish();
     }
 }

chrome/android/webapk/shell_apk/src/org/chromium/webapk/shell_apk/h2o/SplashActivity.java

@@ -104,7 +104,7 @@ public class SplashActivity extends Activity {
         super.onResume();
         mResumed = true;
         if (mResult == ActivityResult.CANCELED) {
-            WebApkUtils.finishAndRemoveTask(this);
+            finish();
             return;
         }