Revert "Mac SxS: Don't ask to take default from other Chromium channels"

This reverts commit e2d335fb.

Reason for revert: This CL triggers a compile error.

Bug: 1110221

Original change's description:
> Mac SxS: Don't ask to take default from other Chromium channels
> 
> If another channel of Chromium is already default, don't ask to
> become default.
> 
> Bug: 1109417
> Change-Id: I095410b47a64731c7ca7fbafa5f3e3427ec89d42
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2318193
> Reviewed-by: Mark Mentovai <mark@chromium.org>
> Commit-Queue: Avi Drissman <avi@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#792144}

TBR=avi@chromium.org,mark@chromium.org

Change-Id: I59a405e113cca1abc28c9c01c34166d572c60c31
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1109417
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2322008Reviewed-by: Hitoshi Yoshida <peria@chromium.org>
Commit-Queue: Hitoshi Yoshida <peria@chromium.org>
Cr-Commit-Position: refs/heads/master@{#792171}

chrome/browser/shell_integration_mac.mm

@@ -9,7 +9,6 @@
 #include "base/mac/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/strings/sys_string_conversions.h"
-#include "build/branding_buildflags.h"
 #include "chrome/common/channel_info.h"
 #include "components/version_info/version_info.h"
 #import "third_party/mozilla/NSWorkspace+Utils.h"
@@ -18,6 +17,20 @@ namespace shell_integration {
 
 namespace {
 
+// Returns true if |identifier| is the bundle id of the default browser.
+bool IsIdentifierDefaultBrowser(NSString* identifier) {
+  NSString* default_browser =
+      [[NSWorkspace sharedWorkspace] defaultBrowserIdentifier];
+  if (!default_browser)
+    return false;
+
+  // We need to ensure we do the comparison case-insensitive as LS doesn't
+  // persist the case of our bundle id.
+  NSComparisonResult result =
+      [default_browser caseInsensitiveCompare:identifier];
+  return result == NSOrderedSame;
+}
+
 // Returns true if |identifier| is the bundle id of the default client
 // application for the given protocol.
 bool IsIdentifierDefaultProtocolClient(NSString* identifier,
@@ -27,7 +40,8 @@ bool IsIdentifierDefaultProtocolClient(NSString* identifier,
   if (!default_client)
     return false;
 
-  // Do the comparison case-insensitively as LS smashes the case.
+  // We need to ensure we do the comparison case-insensitive as LS doesn't
+  // persist the case of our bundle id.
   NSComparisonResult result =
       [base::mac::CFToNSCast(default_client) caseInsensitiveCompare:identifier];
   return result == NSOrderedSame;
@@ -128,51 +142,12 @@ DefaultWebClientState GetDefaultBrowser() {
   if (!my_identifier)
     return UNKNOWN_DEFAULT;
 
-  base::ScopedCFTypeRef<CFStringRef> default_browser_cf(
-      LSCopyDefaultHandlerForURLScheme(CFSTR("http")));
-  if (!default_browser_cf)
-    return NOT_DEFAULT;
-  NSString* default_browser = base::mac::CFToNSCast(default_browser_cf);
-
-  // Do the comparison case-insensitively as LS smashes the case.
-  if ([default_browser caseInsensitiveCompare:my_identifier] == NSOrderedSame)
-    return IS_DEFAULT;
-
-#if BUILDFLAG(GOOGLE_CHROME_BRANDING)
-  // Flavors of Chrome are of the constructions "com.google.Chrome" and
-  // "com.google.Chrome.beta". If the first three components match, then these
-  // are variant flavors.
-  auto three_components_only_lopper = [](NSString* bundle_id) {
-    NSMutableArray<NSString*>* parts =
-        [[bundle_id componentsSeparatedByString:@"."] mutableCopy];
-    while ([parts count] > 3)
-      [parts removeLastObject];
-    return [parts componentsJoinedByString:"."];
-  };
-
-  NSString* my_identifier_lopped = three_components_only_lopper(my_identifier);
-  NSString* default_browser_lopped =
-      three_components_only_lopper(default_browser);
-
-  // Do the comparisons case-insensitively as LS smashes the case.
-  if ([my_identifier_lopped caseInsensitiveCompare:default_browser_lopped] ==
-      NSOrderedSame) {
-    return OTHER_MODE_IS_DEFAULT;
-  }
-#endif  // BUILDFLAG(GOOGLE_CHROME_BRANDING)
-  return NOT_DEFAULT;
+  return IsIdentifierDefaultBrowser(my_identifier) ? IS_DEFAULT : NOT_DEFAULT;
 }
 
 // Returns true if Firefox is the default browser for the current user.
 bool IsFirefoxDefaultBrowser() {
-  base::ScopedCFTypeRef<CFStringRef> default_browser(
-      LSCopyDefaultHandlerForURLScheme(CFSTR("http")));
-  if (!default_browser)
-    return false;
-
-  // Do the comparison case-insensitively as LS smashes the case.
-  return CFStringCompare(default_browser, CFSTR("org.mozilla.firefox"),
-                         kCFCompareCaseInsensitive) == kCFCompareEqualTo;
+  return IsIdentifierDefaultBrowser(@"org.mozilla.firefox");
 }
 
 // Attempt to determine if this instance of Chrome is the default client