[Hera] Excise a bunch of document mode code

Deprecated document mode code is hindering efforts to refactor
other classes.  Excise as much DocumentActivity related code
as possible in one swoop so that it's easy to find later, if
for some reason it's needed.

* Force all users entering DocumentActivity through the migration
  pathway without checking if they're in document mode.  There
  should be no valid way to trigger a DocumentActivity, short of
  being inside Recents when migration is completed and reselecting
  an old Document tab.

* Delete practically everything inside the DocumentActivity class
  to make it easier to determine dead dependencies in classes that
  are being refactored.

* Delete all DocumentActivity-launching related functions from
  ChromeLauncherActivity, and things that spiral out from there.

* Delete most of the document mode tests.

* Deletes a bunch of DocumentTabModel related code.  Migration
  pathways still seem to be intact.

BUG=582539

Review-Url: https://codereview.chromium.org/2011433003
Cr-Commit-Position: refs/heads/master@{#396062}

chrome/android/java/src/org/chromium/chrome/browser/ChromeTabbedActivity.java

@@ -56,7 +56,6 @@
 import org.chromium.chrome.browser.customtabs.CustomTabIntentDataProvider;
 import org.chromium.chrome.browser.device.DeviceClassManager;
 import org.chromium.chrome.browser.document.ChromeLauncherActivity;
-import org.chromium.chrome.browser.document.DocumentUma;
 import org.chromium.chrome.browser.firstrun.FirstRunActivity;
 import org.chromium.chrome.browser.firstrun.FirstRunFlowSequencer;
 import org.chromium.chrome.browser.firstrun.FirstRunSignInProcessor;
@@ -378,10 +377,6 @@ public void onStartWithNative() {
         if (getActivityTab() == null) mLayoutManager.showOverview(false);
 
         resetSavedInstanceState();
-
-        if (FeatureUtilities.isDocumentModeEligible(this)) {
-            DocumentUma.recordInDocumentMode(false);
-        }
     }
 
     @Override

chrome/android/java/src/org/chromium/chrome/browser/document/IncognitoDocumentActivity.java

@@ -4,98 +4,8 @@
 
 package org.chromium.chrome.browser.document;
 
-import android.annotation.TargetApi;
-import android.content.Context;
-import android.os.Build;
-import android.os.Bundle;
-
-import org.chromium.chrome.browser.cookies.CookiesFetcher;
-import org.chromium.chrome.browser.incognito.IncognitoNotificationManager;
-import org.chromium.content.browser.crypto.CipherFactory;
-import org.chromium.content.browser.crypto.CipherFactory.CipherDataObserver;
-
 /**
- *  {@link DocumentActivity} for incognito tabs.
+ * Deprecated, but kept around because it was exported in Chrome's Manifest.
  */
-@TargetApi(Build.VERSION_CODES.LOLLIPOP)
 public class IncognitoDocumentActivity extends DocumentActivity {
-    /**
-     * Responsible for observing when cipher data generation is complete and saving
-     * the new cipher data in the CipherKeyActivity.
-     */
-    private static class CipherKeySaver implements CipherDataObserver {
-        private final Context mContext;
-
-        public CipherKeySaver(Context context) {
-            mContext = context;
-            CipherFactory.getInstance().addCipherDataObserver(this);
-        }
-
-        @Override
-        public void onCipherDataGenerated() {
-            mContext.startActivity(
-                    CipherKeyActivity.createIntent(mContext, null, null));
-            CipherFactory.getInstance().removeCipherDataObserver(this);
-        }
-    }
-
-    private static CipherKeySaver sCipherKeySaver;
-
-    private static void maybeCreateCipherKeySaver(Context context) {
-        if (sCipherKeySaver == null && !CipherFactory.getInstance().hasCipher()) {
-            sCipherKeySaver = new CipherKeySaver(context);
-        }
-    }
-
-    @Override
-    protected boolean isIncognito() {
-        return true;
-    }
-
-    @Override
-    public void preInflationStartup() {
-        CipherFactory.getInstance().restoreFromBundle(getSavedInstanceState());
-        maybeCreateCipherKeySaver(this);
-        super.preInflationStartup();
-    }
-
-    @Override
-    public void onResume() {
-        super.onResume();
-        IncognitoNotificationManager.showIncognitoNotification();
-    }
-
-    @Override
-    public void onResumeWithNative() {
-        super.onResumeWithNative();
-        CookiesFetcher.restoreCookies(this);
-    }
-
-    @Override
-    public void onPauseWithNative() {
-        CookiesFetcher.persistCookies(this);
-        super.onPauseWithNative();
-    }
-
-    @Override
-    public void onSaveInstanceState(Bundle outState) {
-        super.onSaveInstanceState(outState);
-        CipherFactory.getInstance().saveToBundle(outState);
-
-        // Save out the URL that was originally used to spawn this activity because we don't pass it
-        // in through the Intent.
-        String initialUrl = determineInitialUrl(determineTabId());
-        outState.putString(KEY_INITIAL_URL, initialUrl);
-    }
-
-    @Override
-    protected String determineInitialUrl(int tabId) {
-        // Check if the URL was saved in the Bundle.
-        if (getSavedInstanceState() != null) {
-            String initialUrl = getSavedInstanceState().getString(KEY_INITIAL_URL);
-            if (initialUrl != null) return initialUrl;
-        }
-
-        return super.determineInitialUrl(tabId);
-    }
 }