Created the dialog offering the user to merge their account data or keep it

chrome/android/java/AndroidManifest.xml

Index: chrome/android/java/AndroidManifest.xml
diff --git a/chrome/android/java/AndroidManifest.xml b/chrome/android/java/AndroidManifest.xml
index 2cce2a7fabacff693bbf617c930c5134e7becdb4..4359426f61b6c1cc43261c16e9d021499bee7b1b 100644
--- a/chrome/android/java/AndroidManifest.xml
+++ b/chrome/android/java/AndroidManifest.xml
@@ -262,6 +262,10 @@ by a child template that "extends" this file.
             android:windowSoftInputMode="stateHidden|adjustPan"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|mcc|mnc">
         </activity>
+        <activity android:name="org.chromium.chrome.browser.signin.AccountSigninActivity"
+          android:theme="@style/MainTheme"
+          android:launchMode = "singleInstance">

[newt (away), 2016/02/25 06:25:52]

Is singleInstance really what we want? This means that the activity will appear
in a new task (i.e. in recents it will appear as a separate item from the main
Chrome activity)

The docs for <activity> also warn: "singleTask and singleInstance — are not
appropriate for most applications, since they result in an interaction model
that is likely to be unfamiliar to users and is very different from most other
applications."

nit: remove spaces around =

[PEConn, 2016/02/25 14:19:51]

Done.

+        </activity>
         <activity android:name="org.chromium.chrome.browser.preferences.Preferences"
             android:theme="@style/PreferencesTheme"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|mcc|mnc"