Refine the strings on the Incognito NTP and improve the descriptions

components/new_or_sad_tab_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <grit-part>
 
       <message name="IDS_DEFAULT_TAB_TITLE" desc="The default title in a tab.">
         Untitled
       </message>
 
       <!-- Sad Tab Strings -->
       <message name="IDS_SAD_TAB_TITLE" desc="The title of the sad tab page that is shown when a tab crashes. This is intended to be a humorous exclamation of dismay." formatter_data="android_java">
         Aw, Snap!
@@ skipping 125 matching lines @@
         </message>
       </if>
       <message name="IDS_NEW_TAB_UNDO_THUMBNAIL_REMOVE"
          desc="Action link text to undo removing a thumbnail from the most visited section.">
         Undo
       </message>
 
       <!-- Incognito Tab redesign strings -->
       <!-- TODO(msramek): Merge with the above section once this is fully launched. -->
 
-      <message name="IDS_NEW_TAB_OTR_TITLE" desc="Title of the Incognito new tab page." formatter_data="android_java">
+      <message name="IDS_NEW_TAB_OTR_TITLE" desc="Title of the Incognito new tab page. The Incognito mode provides private browsing experience by hiding browsing activity from other people using the same device. However, it does not make the user completely invisible or anonymous; please don't translate it as such." formatter_data="android_java">
         You’ve gone incognito
       </message>
-      <message name="IDS_NEW_TAB_OTR_SUBTITLE" desc="Subtitle of the Incognito new tab page, explaining to the user that the Incognito mode hides their browsing activity from other people using the device." formatter_data="android_java">
-        Now you can browse in private, and other people who use this device won’t see your activity.
+      <message name="IDS_NEW_TAB_OTR_SUBTITLE" desc="Subtitle of the Incognito new tab page, explaining to the user that the Incognito mode hides their browsing activity from other people using the same device. The second sentence clarifies that there are two important exceptions from this rule - downloaded files and added bookmarks will be persisted even after the Incognito session is closed." formatter_data="android_java">
+        Now you can browse privately, and other people who use this device won’t see your activity. However, downloads and bookmarks will be saved.
       </message>
-      <message name="IDS_NEW_TAB_OTR_DISCLAIMER" desc="A disclaimer on the Incognito new tab page, explaining to the user that downloaded files and added bookmarks will be persisted even after the Incognito session is closed." formatter_data="android_java">
-        Downloaded files and bookmarks will be kept.
+      <message name="IDS_NEW_TAB_OTR_NOT_SAVED_BULLET_POINTS" desc="Bullet points listing data that are not saved in the Incognito mode. The '#' character in this text represents a bullet point. Please keep it unchanged and do not add additional spaces around it. The text between the pair of '|' characters will be formatted programmatically to emphasize those words. 'Browsing history' means a history of visited websites. 'Cookies and site data' refers to data saved by websites on the user's device (e.g. sign-in state, preferences, etc.)." formatter_data="android_java">
+        Chrome |won’t save| the following information:#Your browsing history#Cookies and site data

[sdefresne, 2017/03/29 11:39:06]

I don't see where those two messages are used. However, it looks like we usually
use something like the following to add formatting instruction in a translatable
string:

    <ph name="BEGIN_BOLD">&lt;strong&gt;</ph>Caution:<ph
name="END_BOLD">&lt;/strong&gt;</ph>  These files are temporary and may be
automatically deleted to free up disk space.  <ph name="BEGIN_LINK">&lt;a
href="javascript://"&gt;</ph>Learn More<ph
name="END_LINK">&lt;/a&gt;<ex>&lt;/a&gt;</ex></ph>

(from chrome/app/chromeos_strings.grdp)

So instead of adding instructions for translator, could you instead do the
following:

Chrome <ph name="BEGIN_EMPHASIS">&lt;em&gt;<ex>&lt;em&gt;</ex></ph>won't save<ph
name="END_EMPHASIS">&lt;em&gt;<ex>&lt;/em&gt;</ex></ph> the following
information:<ph name="BEGIN_LIST">&lt;em&gt;<ex>&lt;ul&gt;</ex></ph><ph
name="LIST_ITEM_1">&lt;em&gt;<ex>&lt;li&gt;</ex></ph>Your browsing history<ph
name="LIST_ITEM_2">&lt;em&gt;<ex>&lt;li&gt;</ex></ph>Cookies and site data<ph
name="END_LIST">&lt;em&gt;<ex>&lt;/ul&gt;</ex></ph>

or, if you do not / cannot use html, just put | and # in the value for the ph
items:

Chrome <ph name="BEGIN_EMPHASIS">|<ex>&lt;em&gt;</ex></ph>won't save<ph
name="END_EMPHASIS">|<ex>&lt;/em&gt;</ex></ph> the following information:<ph
name="BEGIN_LIST"><ex>&lt;ul&gt;</ex></ph><ph
name="LIST_ITEM_1">#<ex>&lt;li&gt;</ex></ph>Your browsing history<ph
name="LIST_ITEM_2">#<ex>&lt;li&gt;</ex></ph>Cookies and site data<ph
name="END_LIST"><ex>&lt;/ul&gt;</ex></ph>

[msramek, 2017/03/29 15:45:57]

Yeah, the approach with the special characters is what was used in some places
in the old WebUI. I agree that this is better.

I took inspiration from IDS_ENABLE_DEBUGGING_HELP, which means that:
- I left out the <ex> parts which don't really make sense, since we do not
substitute those placeholders
- I formatted the string in a nicer way, since HTML doesn't mind whitespaces

I verified in the translation console that this format was understood well by
the translators :) I verified on the new tab page (but I haven't that CL ready
yet) that the HTML look correct.

As a last minute request from the l10n team, I added translateable=false, as
these strings are supposed to go to the transcreation process and not the usual
translation.

       </message>
-      <message name="IDS_NEW_TAB_OTR_NOT_SAVED_BULLET_POINTS" desc="Bullet points listing data that are not saved in the Incognito mode. The '#' character in this text represents a bullet point. Please keep it unchanged and do not add additional spaces around it. The text between the pair of '|' characters will be highlighted." formatter_data="android_java">
-        This information |won’t be saved|:#Your browsing history#Your searches#Cookie data
-      </message>
-      <message name="IDS_NEW_TAB_OTR_VISIBLE" desc="Bullet points listing entities that might be able to see the user's Incognito activity. The '#' character in this text represents a bullet point. Please keep it unchanged and do not add additional spaces around it. The text between the pair of '|' characters will be highlighted." formatter_data="android_java">
-        Your activity |might still be visible| to:#Websites you visit#Your employer#Your internet service provider
+      <message name="IDS_NEW_TAB_OTR_VISIBLE" desc="Bullet points listing entities that might be able to see the user's Incognito activity. The '#' character in this text represents a bullet point. Please keep it unchanged and do not add additional spaces around it. The text between the pair of '|' characters will be formatted programmatically to emphasize those words. The bullet points elaborate on the fact that Incognito only provides privacy with respect to other users on the same device. Websites you visit still know that you visited them. Your employer, school, and/or internet service provider can still monitor network traffic, even if it comes from the Incognito mode." formatter_data="android_java">
+        Your activity |might still be visible| to:#Websites you visit#Your employer or school#Your internet service provider
       </message>
 
 </grit-part>