chrome: mac: Add Alerts helper app (fixes #3181)

Some Chromium code cleanup will follow in
https://chromium-review.googlesource.com/c/chromium/src/+/4456752

BUILD.gn

@@ -1771,7 +1771,20 @@ if (is_mac) {
       }
     }
 
-    foreach(helper_params, content_mac_helpers) {
+    # From //chrome/BUILD.gn:
+    # Helper app to display alert notifications. This is necessary as an app can
+    # only display either banner or alert style notifications and the main app
+    # will display banners.
+    alert_helper_params = [
+      "alerts",
+      ".alerts",
+      " (Alerts)",
+    ]
+
+    # Merge all helper apps needed by //content and //chrome.
+    chrome_mac_helpers = content_mac_helpers + [ alert_helper_params ]
+
+    foreach(helper_params, chrome_mac_helpers) {
       _helper_target = helper_params[0]
       _helper_bundle_id = helper_params[1]
       _helper_suffix = helper_params[2]
@@ -1802,7 +1815,7 @@ if (is_mac) {
         ":cef_framework",
       ]
 
-      foreach(helper_params, content_mac_helpers) {
+      foreach(helper_params, chrome_mac_helpers) {
         sources += [
           "$root_out_dir/${app_helper_name}${helper_params[2]}.app",
         ]

cmake/cef_variables.cmake.in

@@ -359,6 +359,7 @@ if(OS_MAC)
   # Format is "<name suffix>:<target suffix>:<plist suffix>".
   set(CEF_HELPER_APP_SUFFIXES
     "::"
+    " (Alerts):_alerts:.alerts"
     " (GPU):_gpu:.gpu"
     " (Plugin):_plugin:.plugin"
     " (Renderer):_renderer:.renderer"

libcef/browser/chrome/chrome_content_browser_client_cef.cc

@@ -43,6 +43,12 @@
 #include "third_party/blink/public/common/web_preferences/web_preferences.h"
 #include "third_party/blink/public/mojom/loader/resource_load_info.mojom-shared.h"
 
+#if BUILDFLAG(IS_MAC)
+#include "chrome/browser/child_process_host_flags.h"
+#include "chrome/common/chrome_constants.h"
+#include "libcef/common/util_mac.h"
+#endif
+
 namespace {
 
 void HandleExternalProtocolHelper(
@@ -482,6 +488,20 @@ void ChromeContentBrowserClientCef::RegisterBrowserInterfaceBindersForFrame(
                                                            map);
 }
 
+#if BUILDFLAG(IS_MAC)
+base::FilePath ChromeContentBrowserClientCef::GetChildProcessPath(
+    int child_flags,
+    const base::FilePath& helpers_path) {
+  // Ignoring |helpers_path| here because it doesn't provide sufficient
+  // information to determine the required path for CEF.
+  if (child_flags == chrome::kChildProcessHelperAlerts) {
+    return util_mac::GetChildProcessPath(chrome::kMacHelperSuffixAlerts);
+  }
+  NOTREACHED() << "Unsupported child process flags!";
+  return {};
+}
+#endif  // BUILDFLAG(IS_MAC)
+
 CefRefPtr<CefRequestContextImpl>
 ChromeContentBrowserClientCef::request_context() const {
   return browser_main_parts_->request_context();

libcef/browser/chrome/chrome_content_browser_client_cef.h

@@ -124,6 +124,14 @@ class ChromeContentBrowserClientCef : public ChromeContentBrowserClient {
       content::RenderFrameHost* render_frame_host,
       mojo::BinderMapWithContext<content::RenderFrameHost*>* map) override;
 
+#if BUILDFLAG(IS_MAC)
+  // TODO: Delete after merging
+  // https://chromium-review.googlesource.com/c/chromium/src/+/4456752
+  base::FilePath GetChildProcessPath(
+      int child_flags,
+      const base::FilePath& helpers_path) override;
+#endif  // BUILDFLAG(IS_MAC)
+
   CefRefPtr<CefRequestContextImpl> request_context() const;
 
   scoped_refptr<base::SingleThreadTaskRunner> background_task_runner() const;

libcef/common/util_mac.h

@@ -46,10 +46,13 @@ std::string GetMainBundleID();
 // running in an app bundle.
 base::FilePath GetMainResourcesDirectory();
 
-// Returns the path to the child process executable (e.g. "myapp.app/
-// Contents/Frameworks/myapp Helper.app/Contents/MacOS/myapp Helper"). May
-// return an empty value if not running in an app bundle.
-base::FilePath GetChildProcessPath();
+// Returns the path to the child process executable with optional suffix (e.g.
+// "myapp.app/Contents/Frameworks/myapp Helper<suffix>.app/Contents/MacOS/
+// myapp Helper<suffix>"). May return an empty value if not running in an app
+//  bundle.
+// TODO: Delete after merging
+// https://chromium-review.googlesource.com/c/chromium/src/+/4456752
+base::FilePath GetChildProcessPath(const std::string& suffix);
 
 // Called from MainDelegate::PreSandboxStartup for the main process.
 void PreSandboxStartup();

libcef/common/util_mac.mm

@@ -52,14 +52,27 @@ void OverrideBaseBundleID() {
   base::mac::SetBaseBundleID(bundle_id.c_str());
 }
 
+base::FilePath GetNormalChildProcessPath() {
+  base::FilePath frameworks_path = GetFrameworksPath();
+  if (frameworks_path.empty()) {
+    return base::FilePath();
+  }
+
+  std::string exe_name = GetMainProcessPath().BaseName().value();
+  return frameworks_path.Append(FILE_PATH_LITERAL(exe_name + " Helper.app"))
+      .Append(FILE_PATH_LITERAL("Contents"))
+      .Append(FILE_PATH_LITERAL("MacOS"))
+      .Append(FILE_PATH_LITERAL(exe_name + " Helper"));
+}
+
 void OverrideChildProcessPath() {
   base::FilePath child_process_path =
       base::CommandLine::ForCurrentProcess()->GetSwitchValuePath(
           switches::kBrowserSubprocessPath);
 
   if (child_process_path.empty()) {
-    child_process_path = util_mac::GetChildProcessPath();
-    DCHECK(!child_process_path.empty());
+    child_process_path = GetNormalChildProcessPath();
+    CHECK(!child_process_path.empty());
   }
 
   // Used by ChildProcessHost::GetChildPath and PlatformCrashpadInitialization.
@@ -135,17 +148,29 @@ base::FilePath GetMainResourcesDirectory() {
       .Append(FILE_PATH_LITERAL("Resources"));
 }
 
-base::FilePath GetChildProcessPath() {
-  base::FilePath frameworks_path = GetFrameworksPath();
-  if (frameworks_path.empty()) {
-    return base::FilePath();
+base::FilePath GetChildProcessPath(const std::string& suffix) {
+  // Match the logic in ChildProcessHost::GetChildPath().
+  base::FilePath child_path;
+  base::PathService::Get(content::CHILD_PROCESS_EXE, &child_path);
+  CHECK(!child_path.empty());
+
+  if (suffix.empty()) {
+    // Return the normal child helper path.
+    return child_path;
   }
 
-  std::string exe_name = GetMainProcessPath().BaseName().value();
-  return frameworks_path.Append(FILE_PATH_LITERAL(exe_name + " Helper.app"))
-      .Append(FILE_PATH_LITERAL("Contents"))
-      .Append(FILE_PATH_LITERAL("MacOS"))
-      .Append(FILE_PATH_LITERAL(exe_name + " Helper"));
+  std::string child_base_name = child_path.BaseName().value() + suffix;
+
+  // This is a specialized helper, with the |child_path| at
+  // "myapp.app/Contents/Frameworks/myapp Helper.app/Contents/MacOS/
+  // myapp Helper" Go back up to the "Frameworks" directory to select
+  // a different variant.
+  child_path = child_path.DirName().DirName().DirName().DirName();
+
+  return child_path.Append(child_base_name + ".app")
+      .Append("Contents")
+      .Append("MacOS")
+      .Append(child_base_name);
 }
 
 void PreSandboxStartup() {