Add an activity that allows whitelisted applications to clear all data in Chrome.

chrome/android/java_staging/AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Copyright 2015 The Chromium Authors. All rights reserved.
      Use of this source code is governed by a BSD-style license that can be
      found in the LICENSE file. -->
 
 <!--
 Note: This is a jinja2 template, processed at build time into the final manifest.
 
 Blocks denoted with { % block some_name % }foo{ % endblock % } can be overridden
 by a child template that "extends" this file.
@@ skipping 331 matching lines @@
         <activity android:name="org.chromium.chrome.browser.media.remote.ExpandedControllerActivity"
             android:theme="@style/MainTheme"
             android:label="Chrome.ExpandedControllerActivity"
             android:hardwareAccelerated="true"
             android:launchMode="singleTask"
             android:noHistory="true"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|mcc|mnc"
             android:excludeFromRecents="true">
         </activity>
 
+        <activity android:name="org.chromium.chrome.browser.child_accounts.ResetDataActivity"

[aurimas (slooooooooow), 2015/06/09 17:45:03]

We are exporting this and we will always have to support this so we need to get
this right.

I would vote for removing the underscore from child_accounts and making it
"childaccounts"
Reasoning why:
- I could not find a single _ (underscore) in any package names in Android.
- Google style guide says not to use underscores (I know Android style guide
does not specify it, but it does not use _ either) [1]

Reasons why it is iffy:
- I know we have bad examples (like dom_distiller), but I dont think it is a
good precedent.
- It will make c++ and java directories mismatch (which we already do in several
places)

[1]
https://google-styleguide.googlecode.com/svn/trunk/javaguide.html#s5.2.1-pack...

+            android:theme="@style/Transparent"
+            android:exported="true"
+            android:excludeFromRecents="true">
+        </activity>
+
         <activity android:name="org.chromium.chrome.browser.document.CipherKeyActivity"
             android:launchMode="singleInstance"
             android:theme="@android:style/Theme.Translucent.NoTitleBar"
             android:excludeFromRecents="true">
         </activity>
 
         <!-- Providers for chrome data. -->
         <provider android:name="org.chromium.chrome.browser.ChromeBrowserProviderStaging"
             android:authorities="{{ manifest_package }}.ChromeBrowserProvider;{{ manifest_package }}.browser;{{ manifest_package }}"
             android:exported="true">
@@ skipping 221 matching lines @@
         <meta-data android:name="org.chromium.content.browser.SMART_CLIP_PROVIDER"
             android:value="org.chromium.content.browser.SmartClipProvider"/>
         <meta-data android:name="org.chromium.components.service_tab_launcher.SERVICE_TAB_LAUNCHER"
                    android:value="org.chromium.chrome.browser.ChromeServiceTabLauncher" />
 
         {% block extra_application_definitions %}
         {% endblock %}
     </application>
 </manifest>