[Signin iOS] Update title in merging data dialog

Title should be "Switch Sync Account" when switching, and "Sign in to
Chrome/Chromium" when signing in.

BUG=660418

Review-Url: https://codereview.chromium.org/2629443002
Cr-Commit-Position: refs/heads/master@{#443211}

ios/chrome/app/strings/ios_chromium_strings.grd

@@ -210,6 +210,9 @@ locale.  The strings in this file are specific to iOS.
       <message name="IDS_IOS_OPTIONS_ENABLE_PHYSICAL_WEB_DETAILS" desc="The detailed description of an option to enable scanning for nearby devices broadcasting URLs.">
         Discover web pages sent by nearby objects. When Bluetooth is turned on, Chromium can gather web pages associated with objects around you and send them anonymously to Google to find the most useful ones. <ph name="BEGIN_LINK">BEGIN_LINK</ph>Learn more<ph name="END_LINK">END_LINK</ph>
       </message>
+      <message name="IDS_IOS_OPTIONS_IMPORT_DATA_TITLE_SIGNIN" desc="The title of the Import Data settings screen when signing in. [30em]">
+        Sign in to Chromium
+      </message>
       <message name="IDS_IOS_OPTIONS_PRIVACY_FOOTER" desc="Footer for the clear browsing data dialog [Length: 300em] [iOS only]">
         Chromium may use web services to improve your browsing experience. You may optionally disable these services. <ph name="BEGIN_LINK">BEGIN_LINK</ph>Learn more<ph name="END_LINK">END_LINK</ph>
       </message>

ios/chrome/app/strings/ios_google_chrome_strings.grd

@@ -210,6 +210,9 @@ locale.  The strings in this file are specific to iOS.
       <message name="IDS_IOS_OPTIONS_ENABLE_PHYSICAL_WEB_DETAILS" desc="The detailed description of an option to enable scanning for nearby devices broadcasting URLs.">
         Discover web pages sent by nearby objects. When Bluetooth is turned on, Chrome can gather web pages associated with objects around you and send them anonymously to Google to find the most useful ones. <ph name="BEGIN_LINK">BEGIN_LINK</ph>Learn more<ph name="END_LINK">END_LINK</ph>
       </message>
+      <message name="IDS_IOS_OPTIONS_IMPORT_DATA_TITLE_SIGNIN" desc="The title of the Import Data settings screen when signing in. [30em]">
+        Sign in to Chrome
+      </message>
       <message name="IDS_IOS_OPTIONS_PRIVACY_FOOTER" desc="Footer for the clear browsing data dialog [Length: 300em] [iOS only]">
         Google Chrome may use web services to improve your browsing experience. You may optionally disable these services. <ph name="BEGIN_LINK">BEGIN_LINK</ph>Learn more<ph name="END_LINK">END_LINK</ph>
       </message>

ios/chrome/app/strings/ios_strings.grd

@@ -885,6 +885,9 @@ Handoff must also be enabled in the General section of Settings, and your device
       <message name="IDS_IOS_OPTIONS_IMPORT_DATA_KEEP_TITLE" desc="The title of the Keep Data Separate option on the Import Data settings screen. [60em]">
         Keep my data separate
       </message>
+      <message name="IDS_IOS_OPTIONS_IMPORT_DATA_TITLE_SWITCH" desc="The title of the Import Data settings screen when switching accounts. [30em]">
+        Switch Sync Account
+      </message>
       <message name="IDS_IOS_OPTIONS_PRELOAD_WEBPAGES" desc="Title for opening the setting for if/when to preload webpages. [Length: 20em] [iOS only]">
         Preload Webpages
       </message>

ios/chrome/browser/ui/settings/import_data_collection_view_controller.mm

@@ -15,6 +15,7 @@
 #import "ios/chrome/browser/ui/collection_view/collection_view_model.h"
 #import "ios/chrome/browser/ui/settings/cells/card_multiline_item.h"
 #import "ios/chrome/browser/ui/settings/cells/import_data_multiline_detail_cell.h"
+#include "ios/chrome/grit/ios_chromium_strings.h"
 #include "ios/chrome/grit/ios_strings.h"
 #import "ios/third_party/material_components_ios/src/components/CollectionCells/src/MaterialCollectionCells.h"
 #import "ios/third_party/material_components_ios/src/components/Collections/src/MaterialCollections.h"
@@ -67,6 +68,10 @@ typedef NS_ENUM(NSInteger, ItemType) {
     _isSignedIn = isSignedIn;
     _shouldClearData = isSignedIn ? SHOULD_CLEAR_DATA_CLEAR_DATA
                                   : SHOULD_CLEAR_DATA_MERGE_DATA;
+    self.title =
+        isSignedIn
+            ? l10n_util::GetNSString(IDS_IOS_OPTIONS_IMPORT_DATA_TITLE_SWITCH)
+            : l10n_util::GetNSString(IDS_IOS_OPTIONS_IMPORT_DATA_TITLE_SIGNIN);
     [self setShouldHideDoneButton:YES];
     self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc]
         initWithTitle:l10n_util::GetNSString(