Don't double-prompt for uses of facetime:// and tel:// URLs.

ios/chrome/browser/web/external_app_launcher.mm

Index: ios/chrome/browser/web/external_app_launcher.mm
diff --git a/ios/chrome/browser/web/external_app_launcher.mm b/ios/chrome/browser/web/external_app_launcher.mm
index 74b5023071bb45c8beaa45d4cd80a0a928d74629..5c987b23a31e049dd86527f8e7ad39d5229f373e 100644
--- a/ios/chrome/browser/web/external_app_launcher.mm
+++ b/ios/chrome/browser/web/external_app_launcher.mm
@@ -4,6 +4,7 @@
 
 #import "ios/chrome/browser/web/external_app_launcher.h"
 
+#include "base/ios/ios_util.h"
 #include "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
@@ -52,8 +53,8 @@ void RecordExternalApplicationOpened(bool opened) {
 @interface ExternalAppLauncher ()
 // Returns the Phone/FaceTime call argument from |URL|.
 + (NSString*)formatCallArgument:(NSURL*)URL;
-// Ask user for confirmation before dialing FaceTime destination.
-- (void)openFaceTimePromptForURL:(NSURL*)telURL;
+// Ask user for confirmation before dialing Phone or FaceTime destinations.
+- (void)openPromptForURL:(NSURL*)telURL;

[Eugene But (OOO till 7-30), 2017/04/13 22:47:30]

s/telURL/URL ?

[pkl (ping after 24h if needed), 2017/04/14 00:34:50]

Done.

 // Ask user for confirmation before moving to external app.
 - (void)openExternalAppWithPromptForURL:(NSURL*)URL;
 // Presents a configured alert controller on the root view controller.
@@ -96,8 +97,10 @@ void RecordExternalApplicationOpened(bool opened) {
       }];
 }
 
-- (void)openFaceTimePromptForURL:(NSURL*)URL {
-  NSString* openTitle = l10n_util::GetNSString(IDS_IOS_FACETIME_BUTTON);
+- (void)openPromptForURL:(NSURL*)URL {
+  NSString* openTitle = [URL.scheme isEqualToString:@"facetime"]

[Eugene But (OOO till 7-30), 2017/04/13 22:47:30]

Do you want to DCHECK that URL.scheme is ether facetime, tel or facetime-audio?

[pkl (ping after 24h if needed), 2017/04/14 00:34:50]

Refactored into a anonymous function and do the NOTREACHED() there.

+                            ? l10n_util::GetNSString(IDS_IOS_FACETIME_BUTTON)
+                            : l10n_util::GetNSString(IDS_IOS_PHONE_CALL_BUTTON);
   [self presentAlertControllerWithMessage:[[self class] formatCallArgument:URL]
                                 openTitle:openTitle
                               openHandler:^(UIAlertAction* action) {
@@ -136,26 +139,22 @@ void RecordExternalApplicationOpened(bool opened) {
     return NO;
   NSURL* URL = net::NSURLWithGURL(gURL);
 
-  if (gURL.SchemeIs("facetime") || gURL.SchemeIs("facetime-audio")) {
+  // iOS 10.3.2 introduced new prompts when facetime: and facetime-audio:
+  // URL schemes are opened. It is no longer necessary for Chrome to present
+  // another prompt before the system-provided prompt.
+  if (!base::ios::IsRunningOnOrLater(10, 3, 2) &&
+      (gURL.SchemeIs("tel") || gURL.SchemeIs("facetime") ||

[Eugene But (OOO till 7-30), 2017/04/13 22:47:30]

Do you want to create constants for these custom url schemes?

[pkl (ping after 24h if needed), 2017/04/14 00:34:50]

Refactored so all the strings are nearby to not clutter the logic here. I find
consts for these common strings don't always improve readability.

+       gURL.SchemeIs("facetime-audio"))) {
     // Showing an alert view immediately has a side-effect where focus is
     // taken from the UIWebView so quickly that mouseup events are lost and
     // buttons get 'stuck' in the on position. The solution is to defer
     // showing the view.
-    [self performSelector:@selector(openFaceTimePromptForURL:)
+    [self performSelector:@selector(openPromptForURL:)
                withObject:URL
                afterDelay:0.0];
     return YES;
   }
 
-  // Use telprompt instead of tel because telprompt returns user back to
-  // Chrome after phone call is completed/aborted.
-  if (gURL.SchemeIs("tel")) {
-    GURL::Replacements replacements;
-    replacements.SetSchemeStr("telprompt");
-    URL = net::NSURLWithGURL(gURL.ReplaceComponents(replacements));
-    DCHECK([[URL scheme] isEqualToString:@"telprompt"]);
-  }
-
   // Don't open external application if chrome is not active.
   if ([[UIApplication sharedApplication] applicationState] !=
       UIApplicationStateActive)