chrome: Add callback for already running app relaunch (fixes #3609)

Adds a new CefBrowserProcessHandler::OnAlreadyRunningAppRelaunch
callback for when an already running app is relaunched with the
same CefSettings.root_cache_path.

Client apps should check the CefInitialize() return value for early
exit of the relaunch source process.

patch/patches/chrome_browser.patch

@@ -1,5 +1,5 @@
 diff --git chrome/browser/BUILD.gn chrome/browser/BUILD.gn
-index bce36d7ffb408..33fdb680fb20a 100644
+index bce36d7ffb408..3e8fd566a375c 100644
 --- chrome/browser/BUILD.gn
 +++ chrome/browser/BUILD.gn
 @@ -11,6 +11,7 @@ import("//build/config/compiler/pgo/pgo.gni")
@@ -10,17 +10,7 @@ index bce36d7ffb408..33fdb680fb20a 100644
  import("//chrome/browser/buildflags.gni")
  import("//chrome/browser/downgrade/buildflags.gni")
  import("//chrome/common/features.gni")
-@@ -110,7 +111,8 @@ buildflag_header("buildflags") {
- 
-   # Android and ChromeOS don't support multiple browser processes, so they don't
-   # employ ProcessSingleton.
--  if (is_android || is_chromeos) {
-+  # Also disable for CEF (see issue #3609).
-+  if (is_android || is_chromeos || enable_cef) {
-     flags += [ "ENABLE_PROCESS_SINGLETON=0" ]
-   } else {
-     flags += [ "ENABLE_PROCESS_SINGLETON=1" ]
-@@ -2073,6 +2075,7 @@ static_library("browser") {
+@@ -2073,6 +2074,7 @@ static_library("browser") {
      "//build/config/chromebox_for_meetings:buildflags",
      "//build/config/compiler:compiler_buildflags",
      "//cc",
@@ -28,7 +18,7 @@ index bce36d7ffb408..33fdb680fb20a 100644
      "//chrome:extra_resources",
      "//chrome:resources",
      "//chrome:strings",
-@@ -2729,6 +2732,10 @@ static_library("browser") {
+@@ -2729,6 +2731,10 @@ static_library("browser") {
      ]
    }
  
@@ -39,37 +29,3 @@ index bce36d7ffb408..33fdb680fb20a 100644
    if (is_android) {
      sources += [
        "accessibility/accessibility_prefs/android/accessibility_prefs_controller.cc",
-diff --git chrome/browser/browser_process_platform_part_win.cc chrome/browser/browser_process_platform_part_win.cc
-index 66fa1aa8b10b3..9b506f6d153ae 100644
---- chrome/browser/browser_process_platform_part_win.cc
-+++ chrome/browser/browser_process_platform_part_win.cc
-@@ -9,6 +9,7 @@
- BrowserProcessPlatformPart::BrowserProcessPlatformPart() = default;
- BrowserProcessPlatformPart::~BrowserProcessPlatformPart() = default;
- 
-+#if BUILDFLAG(ENABLE_PROCESS_SINGLETON)
- void BrowserProcessPlatformPart::OnBrowserLaunch() {
-   if constexpr (kShouldRecordActiveUse) {
-     if (!did_run_updater_) {
-@@ -16,3 +17,4 @@ void BrowserProcessPlatformPart::OnBrowserLaunch() {
-     }
-   }
- }
-+#endif  // BUILDFLAG(ENABLE_PROCESS_SINGLETON)
-diff --git chrome/browser/browser_process_platform_part_win.h chrome/browser/browser_process_platform_part_win.h
-index fc4b9808f3f6e..92cef9459811f 100644
---- chrome/browser/browser_process_platform_part_win.h
-+++ chrome/browser/browser_process_platform_part_win.h
-@@ -18,10 +18,12 @@ class BrowserProcessPlatformPart : public BrowserProcessPlatformPartBase {
-   ~BrowserProcessPlatformPart() override;
- 
-   // BrowserProcessPlatformPartBase:
-+#if BUILDFLAG(ENABLE_PROCESS_SINGLETON)
-   void OnBrowserLaunch() override;
- 
-  private:
-   absl::optional<DidRunUpdater> did_run_updater_;
-+#endif  // BUILDFLAG(ENABLE_PROCESS_SINGLETON)
- };
- 
- #endif  // CHROME_BROWSER_BROWSER_PROCESS_PLATFORM_PART_WIN_H_

patch/patches/chrome_browser_startup.patch

@@ -0,0 +1,70 @@
+diff --git chrome/browser/ui/startup/startup_browser_creator.cc chrome/browser/ui/startup/startup_browser_creator.cc
+index cef85a137d3e2..985d716ec7549 100644
+--- chrome/browser/ui/startup/startup_browser_creator.cc
++++ chrome/browser/ui/startup/startup_browser_creator.cc
+@@ -578,6 +578,14 @@ void OpenNewWindowForFirstRun(
+                                 is_first_run, std::move(launch_mode_recorder));
+ }
+ #endif  // BUILDFLAG(IS_CHROMEOS_LACROS) || BUILDFLAG(ENABLE_DICE_SUPPORT)
++
++StartupBrowserCreator::ProcessCommandLineCallback*
++GetProcessCommandLineCallback() {
++  static base::NoDestructor<StartupBrowserCreator::ProcessCommandLineCallback>
++      callback;
++  return callback.get();
++}
++
+ }  // namespace
+ 
+ StartupProfileMode StartupProfileModeFromReason(
+@@ -1441,6 +1449,12 @@ void StartupBrowserCreator::ProcessCommandLineWithProfile(
+       {profile, mode}, last_opened_profiles);
+ }
+ 
++// static
++void StartupBrowserCreator::RegisterProcessCommandLineCallback(
++    ProcessCommandLineCallback cb) {
++  *GetProcessCommandLineCallback() = cb;
++}
++
+ // static
+ void StartupBrowserCreator::ProcessCommandLineAlreadyRunning(
+     const base::CommandLine& command_line,
+@@ -1450,6 +1464,11 @@ void StartupBrowserCreator::ProcessCommandLineAlreadyRunning(
+     return;
+   }
+ 
++  auto* cb = GetProcessCommandLineCallback();
++  if (!cb->is_null() && cb->Run(command_line, cur_dir)) {
++    return;
++  }
++
+   Profile* profile = nullptr;
+   StartupProfileMode mode =
+       StartupProfileModeFromReason(profile_path_info.reason);
+diff --git chrome/browser/ui/startup/startup_browser_creator.h chrome/browser/ui/startup/startup_browser_creator.h
+index e22ea9b782910..68724228e79f5 100644
+--- chrome/browser/ui/startup/startup_browser_creator.h
++++ chrome/browser/ui/startup/startup_browser_creator.h
+@@ -9,6 +9,7 @@
+ #include <vector>
+ 
+ #include "base/files/file_path.h"
++#include "base/functional/callback.h"
+ #include "base/gtest_prod_util.h"
+ #include "base/memory/raw_ptr.h"
+ #include "build/build_config.h"
+@@ -136,6 +137,13 @@ class StartupBrowserCreator {
+              StartupProfileInfo profile_info,
+              const Profiles& last_opened_profiles);
+ 
++  // Registers a callback that will be executed each time
++  // ProcessCommandLineAlreadyRunning is called.
++  using ProcessCommandLineCallback = base::RepeatingCallback<bool(
++      const base::CommandLine& command_line,
++      const base::FilePath& cur_dir)>;
++  static void RegisterProcessCommandLineCallback(ProcessCommandLineCallback cb);
++
+   // This function performs command-line handling and is invoked only after
+   // start up (for example when we get a start request for another process).
+   // |command_line| holds the command line we need to process.

patch/patches/chrome_runtime.patch

@@ -1,5 +1,5 @@
 diff --git chrome/app/chrome_main_delegate.cc chrome/app/chrome_main_delegate.cc
-index dc84cbd4c97d1..b8a1dd5a19be1 100644
+index dc84cbd4c97d1..696af79e6cec5 100644
 --- chrome/app/chrome_main_delegate.cc
 +++ chrome/app/chrome_main_delegate.cc
 @@ -41,6 +41,7 @@
@@ -30,6 +30,15 @@ index dc84cbd4c97d1..b8a1dd5a19be1 100644
  absl::optional<int> ChromeMainDelegate::PostEarlyInitialization(
      InvokedIn invoked_in) {
    DCHECK(base::ThreadPoolInstance::Get());
+@@ -782,7 +789,7 @@ absl::optional<int> ChromeMainDelegate::PostEarlyInitialization(
+     // future session's metrics.
+     DeferBrowserMetrics(user_data_dir);
+ 
+-#if BUILDFLAG(IS_WIN)
++#if BUILDFLAG(IS_WIN) && !BUILDFLAG(ENABLE_CEF)
+     // In the case the process is not the singleton process, the uninstall tasks
+     // need to be executed here. A window will be displayed asking to close all
+     // running instances.
 @@ -946,7 +953,8 @@ absl::optional<int> ChromeMainDelegate::PostEarlyInitialization(
  
    if (base::FeatureList::IsEnabled(
@@ -126,7 +135,7 @@ index 176b6248f18e8..1360e8c209eba 100644
  #if BUILDFLAG(IS_CHROMEOS_LACROS)
    std::unique_ptr<chromeos::LacrosService> lacros_service_;
 diff --git chrome/browser/chrome_browser_main.cc chrome/browser/chrome_browser_main.cc
-index e819129536dc0..d0f1e684ae019 100644
+index e819129536dc0..e9287f6e03a88 100644
 --- chrome/browser/chrome_browser_main.cc
 +++ chrome/browser/chrome_browser_main.cc
 @@ -52,6 +52,7 @@
@@ -137,6 +146,15 @@ index e819129536dc0..d0f1e684ae019 100644
  #include "chrome/browser/about_flags.h"
  #include "chrome/browser/active_use_util.h"
  #include "chrome/browser/after_startup_task_utils.h"
+@@ -486,7 +487,7 @@ void ProcessSingletonNotificationCallbackImpl(
+     return;
+   }
+ 
+-#if BUILDFLAG(IS_WIN)
++#if BUILDFLAG(IS_WIN) && !BUILDFLAG(ENABLE_CEF)
+   // The uninstall command-line switch is handled by the origin process; see
+   // ChromeMainDelegate::PostEarlyInitialization(...). The other process won't
+   // be able to become the singleton process and will display a window asking
 @@ -774,7 +775,7 @@ int ChromeBrowserMainParts::PreEarlyInitialization() {
      return content::RESULT_CODE_NORMAL_EXIT;
    }