MacPWAs: Fix file handlers

In r750774, web_app::ShortcutInfo::file_handler_extensions was
changed from stripping off the leading `.` to not stripping
off the leading `.`. This broke the macOS implementation, because
these values are listed directly in CFBundleTypeExtensions in the
Info.plist.

Fix this by stripping the leading `.` in a helper function, and
updating the unit tests to verify this behavior.

Bug: 1067368
Change-Id: I222fbd8a342cc1f13bc271bfe59a1aad8989b889
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2136470
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: Alexey Baskakov <loyso@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756581}

chrome/browser/web_applications/components/web_app_shortcut_mac.mm

@@ -211,6 +211,19 @@ bool IsImageValidForIcon(const gfx::Image& image) {
   return false;
 }
 
+// Remove the leading . from the entries of |extensions|. Any items that do not
+// have a leading . are removed.
+std::set<std::string> GetFileHandlerExtensionsWithoutDot(
+    const std::set<std::string>& file_extensions) {
+  std::set<std::string> result;
+  for (const auto& file_extension : file_extensions) {
+    if (file_extension.length() <= 1 || file_extension[0] != '.')
+      continue;
+    result.insert(file_extension.substr(1));
+  }
+  return result;
+}
+
 bool AppShimCreationDisabledForTest() {
   // Disable app shims in tests because shims created in ~/Applications will not
   // be cleaned up.
@@ -1024,17 +1037,19 @@ bool WebAppShortcutCreator::UpdatePlist(const base::FilePath& app_path) const {
             forKey:app_mode::kNSHighResolutionCapableKey];
 
   // 3. Fill in file handlers.
-  if (!info_->file_handler_extensions.empty() ||
+  const auto file_handler_extensions =
+      GetFileHandlerExtensionsWithoutDot(info_->file_handler_extensions);
+  if (!file_handler_extensions.empty() ||
       !info_->file_handler_mime_types.empty()) {
     base::scoped_nsobject<NSMutableArray> doc_types_value(
         [[NSMutableArray alloc] init]);
     base::scoped_nsobject<NSMutableDictionary> doc_types_dict(
         [[NSMutableDictionary alloc] init]);
-    if (!info_->file_handler_extensions.empty()) {
+    if (!file_handler_extensions.empty()) {
       base::scoped_nsobject<NSMutableArray> extensions(
           [[NSMutableArray alloc] init]);
-      for (const auto& extension : info_->file_handler_extensions)
-        [extensions addObject:base::SysUTF8ToNSString(extension)];
+      for (const auto& file_extension : file_handler_extensions)
+        [extensions addObject:base::SysUTF8ToNSString(file_extension)];
       [doc_types_dict setObject:extensions
                          forKey:app_mode::kCFBundleTypeExtensionsKey];
     }

chrome/browser/web_applications/components/web_app_shortcut_mac_unittest.mm

@@ -219,8 +219,10 @@ TEST_F(WebAppShortcutCreatorTest, FileHandlers) {
   }
   EXPECT_TRUE(base::DeleteFileRecursively(shim_path_));
 
-  // Register 2 mime types. We should now have kCFBundleTypeMIMETypesKey but
-  // not kCFBundleTypeExtensionsKey.
+  // Register 2 mime types (and 2 invalid extensions). We should now have
+  // kCFBundleTypeMIMETypesKey but not kCFBundleTypeExtensionsKey.
+  info_->file_handler_extensions.insert("byobb");
+  info_->file_handler_extensions.insert(".");
   info_->file_handler_mime_types.insert("foo/bar");
   info_->file_handler_mime_types.insert("moo/cow");
   EXPECT_TRUE(shortcut_creator.CreateShortcuts(SHORTCUT_CREATION_AUTOMATED,
@@ -249,10 +251,10 @@ TEST_F(WebAppShortcutCreatorTest, FileHandlers) {
   }
   EXPECT_TRUE(base::DeleteFileRecursively(shim_path_));
 
-  // Register 3 extensions with the 2 mime types.
-  info_->file_handler_extensions.insert("cow");
-  info_->file_handler_extensions.insert("pig");
-  info_->file_handler_extensions.insert("bbq");
+  // Register 3 valid extensions (and 2 invalid ones) with the 2 mime types.
+  info_->file_handler_extensions.insert(".cow");
+  info_->file_handler_extensions.insert(".pig");
+  info_->file_handler_extensions.insert(".bbq");
   EXPECT_TRUE(shortcut_creator.CreateShortcuts(SHORTCUT_CREATION_AUTOMATED,
                                                ShortcutLocations()));
   {