[ios] Save HTTP(S) URL open timestamp

This change saves the last time an HTTP(S) link was opened. It
will be used to identify default browser usage.

Bug: 1107489
Change-Id: I27fed2285dd42a44bbdcfa6c4043a12b4bc30e5c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2320079
Commit-Queue: Chris Lu <thegreenfrog@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792972}

ios/chrome/app/startup/chrome_app_startup_parameters.h

@@ -38,6 +38,10 @@ 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

@@ -77,6 +77,8 @@ enum SearchExtensionAction {
 
 }  // namespace
 
+NSString* const kLastHTTPURLOpenTime = @"lastHTTPURLOpenTime";
+
 @implementation ChromeAppStartupParameters {
   NSString* _secureSourceApp;
   NSString* _declaredSourceApp;
@@ -185,6 +187,12 @@ enum SearchExtensionAction {
     UMA_HISTOGRAM_ENUMERATION(kUMAMobileSessionStartActionHistogram, action,
                               MOBILE_SESSION_START_ACTION_COUNT);
 
+    if (action == START_ACTION_OPEN_HTTP_FROM_OS ||
+        action == START_ACTION_OPEN_HTTPS_FROM_OS) {
+      [[NSUserDefaults standardUserDefaults] setObject:[NSDate date]
+                                                forKey:kLastHTTPURLOpenTime];
+    }
+
     if (!externalURL.is_valid())
       return nil;
     return [[ChromeAppStartupParameters alloc] initWithExternalURL:externalURL