[ios] Add IsChromeLikelyDefaultBrowser

This new method will be used to determine if the user is likely
using Chrome as the default Browser for metrics logging
and when to present default browser promotional UI.

Bug: 1107489
Change-Id: I642a7de704f84c7564aea08d90a512cf08a1078a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2348207Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Chris Lu <thegreenfrog@chromium.org>
Auto-Submit: Chris Lu <thegreenfrog@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797499}

ios/chrome/app/startup/chrome_app_startup_parameters.h

@@ -38,10 +38,6 @@ enum MobileSessionCallerApp {
   MOBILE_SESSION_CALLER_APP_COUNT,
 };
 
-// UserDefaults key that saves the last time an HTTP(S) link was sent and opened
-// by the app.
-extern NSString* const kLastHTTPURLOpenTime;
-
 @interface ChromeAppStartupParameters : AppStartupParameters
 
 - (instancetype)initWithExternalURL:(const GURL&)externalURL

ios/chrome/app/startup/chrome_app_startup_parameters.mm

@@ -78,8 +78,6 @@ enum SearchExtensionAction {
 
 }  // namespace
 
-NSString* const kLastHTTPURLOpenTime = @"lastHTTPURLOpenTime";
-
 @implementation ChromeAppStartupParameters {
   NSString* _secureSourceApp;
   NSString* _declaredSourceApp;

ios/chrome/browser/ui/whats_new/default_browser_utils.h

@@ -5,10 +5,20 @@
 #ifndef IOS_CHROME_BROWSER_UI_WHATS_NEW_DEFAULT_BROWSER_UTILS_H_
 #define IOS_CHROME_BROWSER_UI_WHATS_NEW_DEFAULT_BROWSER_UTILS_H_
 
+#import <UIKit/UIKit.h>
+
+// UserDefaults key that saves the last time an HTTP(S) link was sent and opened
+// by the app.
+extern NSString* const kLastHTTPURLOpenTime;
+
 // Logs the timestamp of user activity that is deemed to be an indication of
 // a user that would likely benefit from having Chrome set as their default
 // browser. Before logging the current activity, this method will also clear all
 // past expired logs that have happened too far in the past.
 void LogLikelyInterestedDefaultBrowserUserActivity();
 
+// Returns True if the last URL open is within the time threshold that would
+// indicate Chrome is likely still the default browser. Returns False otherwise.
+bool IsChromeLikelyDefaultBrowser();
+
 #endif  // IOS_CHROME_BROWSER_UI_WHATS_NEW_DEFAULT_BROWSER_UTILS_H_

ios/chrome/browser/ui/whats_new/default_browser_utils.mm

@@ -16,8 +16,13 @@ NSString* const kLastSignificantUserEvent = @"lastSignificantUserEvent";
 // Time threshold before activity timestamps should be removed. Currently set to
 // seven days.
 const NSTimeInterval kUserActivityTimestampExpiration = 7 * 24 * 60 * 60;
+// Time threshold for the last URL open before no URL opens likely indicates
+// Chrome is no longer the default browser.
+const NSTimeInterval kLatestURLOpenForDefaultBrowser = 7 * 24 * 60 * 60;
 }
 
+NSString* const kLastHTTPURLOpenTime = @"lastHTTPURLOpenTime";
+
 void LogLikelyInterestedDefaultBrowserUserActivity() {
   NSMutableArray<NSDate*>* pastUserEvents =
       [[[NSUserDefaults standardUserDefaults]
@@ -42,3 +47,18 @@ void LogLikelyInterestedDefaultBrowserUserActivity() {
   [[NSUserDefaults standardUserDefaults] setObject:pastUserEvents
                                             forKey:kLastSignificantUserEvent];
 }
+
+bool IsChromeLikelyDefaultBrowser() {
+  NSDate* lastURLOpen =
+      [[NSUserDefaults standardUserDefaults] objectForKey:kLastHTTPURLOpenTime];
+  if (!lastURLOpen) {
+    return false;
+  }
+
+  NSDate* sevenDaysAgoDate =
+      [NSDate dateWithTimeIntervalSinceNow:-kLatestURLOpenForDefaultBrowser];
+  if ([lastURLOpen laterDate:sevenDaysAgoDate] == sevenDaysAgoDate) {
+    return false;
+  }
+  return true;
+}