refactor: Add ElectronBrowserContext::BrowserContexts() (#46158)

* refactor: add ElectronBrowserContext::BrowserContexts()

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* refactor: use ElectronBrowserContext::BrowserContexts() in ElectronBrowserMainParts::PostMainMessageLoopRun()

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* refactor: use ElectronBrowserContext::BrowserContexts() in ElectronExtensionsBrowserClient::IsValidContext()

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* refactor: use ElectronBrowserContext::BrowserContexts() in ElectronExtensionsBrowserClient::BroadcastEventToRenderers()

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* refactor: move PartitionKey, BrowserContextMap private

Co-authored-by: Charles Kerr <charles@charleskerr.com>

* refactor: add ElectronBrowserContext::IsValidContext()

decouple ElectronExtensionsBrowserClient from the internals of ElectronBrowserContext

Co-authored-by: Charles Kerr <charles@charleskerr.com>

---------

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Charles Kerr <charles@charleskerr.com>

shell/browser/electron_browser_context.cc

@@ -12,6 +12,7 @@
 #include "base/barrier_closure.h"
 #include "base/base_paths.h"
 #include "base/command_line.h"
+#include "base/containers/to_vector.h"
 #include "base/files/file_path.h"
 #include "base/no_destructor.h"
 #include "base/path_service.h"
@@ -308,19 +309,50 @@ bool DoesDeviceMatch(const base::Value& device,
   return false;
 }
 
+// partition_id => browser_context
+struct PartitionKey {
+  PartitionKey(const std::string_view partition, bool in_memory)
+      : type_{Type::Partition}, location_{partition}, in_memory_{in_memory} {}
+
+  explicit PartitionKey(const base::FilePath& file_path)
+      : type_{Type::Path},
+        location_{file_path.AsUTF8Unsafe()},
+        in_memory_{false} {}
+
+  friend auto operator<=>(const PartitionKey&, const PartitionKey&) = default;
+
+ private:
+  enum class Type { Partition, Path };
+
+  Type type_;
+  std::string location_;
+  bool in_memory_;
+};
+
+[[nodiscard]] auto& ContextMap() {
+  static base::NoDestructor<
+      std::map<PartitionKey, std::unique_ptr<ElectronBrowserContext>>>
+      map;
+  return *map;
+}
+
 }  // namespace
 
 // static
-ElectronBrowserContext::BrowserContextMap&
-ElectronBrowserContext::browser_context_map() {
-  static base::NoDestructor<ElectronBrowserContext::BrowserContextMap>
-      browser_context_map;
-  return *browser_context_map;
+std::vector<ElectronBrowserContext*> ElectronBrowserContext::BrowserContexts() {
+  return base::ToVector(ContextMap(),
+                        [](auto& iter) { return iter.second.get(); });
+}
+
+bool ElectronBrowserContext::IsValidContext(const void* context) {
+  return std::ranges::any_of(ContextMap(), [context](const auto& iter) {
+    return iter.second.get() == context;
+  });
 }
 
 // static
 void ElectronBrowserContext::DestroyAllContexts() {
-  auto& map = browser_context_map();
+  auto& map = ContextMap();
   // Avoid UAF by destroying the default context last. See ba629e3 for info.
   const auto extracted = map.extract(PartitionKey{"", false});
   map.clear();
@@ -841,7 +873,7 @@ ElectronBrowserContext* ElectronBrowserContext::From(
     const std::string& partition,
     bool in_memory,
     base::Value::Dict options) {
-  auto& context = browser_context_map()[PartitionKey(partition, in_memory)];
+  auto& context = ContextMap()[PartitionKey(partition, in_memory)];
   if (!context) {
     context.reset(new ElectronBrowserContext{std::cref(partition), in_memory,
                                              std::move(options)});
@@ -858,7 +890,7 @@ ElectronBrowserContext* ElectronBrowserContext::GetDefaultBrowserContext(
 ElectronBrowserContext* ElectronBrowserContext::FromPath(
     const base::FilePath& path,
     base::Value::Dict options) {
-  auto& context = browser_context_map()[PartitionKey(path)];
+  auto& context = ContextMap()[PartitionKey(path)];
   if (!context) {
     context.reset(
         new ElectronBrowserContext{std::cref(path), false, std::move(options)});

shell/browser/electron_browser_context.h

@@ -61,28 +61,9 @@ class ElectronBrowserContext : public content::BrowserContext {
   ElectronBrowserContext(const ElectronBrowserContext&) = delete;
   ElectronBrowserContext& operator=(const ElectronBrowserContext&) = delete;
 
-  // partition_id => browser_context
-  struct PartitionKey {
-    PartitionKey(const std::string_view partition, bool in_memory)
-        : type_{Type::Partition}, location_{partition}, in_memory_{in_memory} {}
+  [[nodiscard]] static std::vector<ElectronBrowserContext*> BrowserContexts();
 
-    explicit PartitionKey(const base::FilePath& file_path)
-        : type_{Type::Path},
-          location_{file_path.AsUTF8Unsafe()},
-          in_memory_{false} {}
-
-    friend auto operator<=>(const PartitionKey&, const PartitionKey&) = default;
-
-   private:
-    enum class Type { Partition, Path };
-
-    Type type_;
-    std::string location_;
-    bool in_memory_;
-  };
-
-  using BrowserContextMap =
-      std::map<PartitionKey, std::unique_ptr<ElectronBrowserContext>>;
+  [[nodiscard]] static bool IsValidContext(const void* context);
 
   // Get or create the default BrowserContext.
   static ElectronBrowserContext* GetDefaultBrowserContext(
@@ -101,8 +82,6 @@ class ElectronBrowserContext : public content::BrowserContext {
   static ElectronBrowserContext* FromPath(const base::FilePath& path,
                                           base::Value::Dict options = {});
 
-  static BrowserContextMap& browser_context_map();
-
   static void DestroyAllContexts();
 
   void SetUserAgent(const std::string& user_agent);

shell/browser/electron_browser_main_parts.cc

@@ -554,12 +554,10 @@ void ElectronBrowserMainParts::PostMainMessageLoopRun() {
 
   // Shutdown the DownloadManager before destroying Node to prevent
   // DownloadItem callbacks from crashing.
-  for (auto& iter : ElectronBrowserContext::browser_context_map()) {
-    auto* download_manager = iter.second.get()->GetDownloadManager();
-    if (download_manager) {
+  for (auto* browser_context : ElectronBrowserContext::BrowserContexts()) {
+    if (auto* download_manager = browser_context->GetDownloadManager())
       download_manager->Shutdown();
   }
-  }
 
   // Shutdown utility process created with Electron API before
   // stopping Node.js so that exit events can be emitted. We don't let

shell/browser/extensions/electron_extensions_browser_client.cc

@@ -84,12 +84,7 @@ bool ElectronExtensionsBrowserClient::AreExtensionsDisabled(
 }
 
 bool ElectronExtensionsBrowserClient::IsValidContext(void* context) {
-  auto& context_map = ElectronBrowserContext::browser_context_map();
-  for (auto const& entry : context_map) {
-    if (entry.second && entry.second.get() == context)
-      return true;
-  }
-  return false;
+  return ElectronBrowserContext::IsValidContext(context);
 }
 
 bool ElectronExtensionsBrowserClient::IsSameContext(BrowserContext* first,
@@ -340,14 +335,11 @@ void ElectronExtensionsBrowserClient::BroadcastEventToRenderers(
     return;
   }
 
-  for (auto const& [key, browser_context] :
-       ElectronBrowserContext::browser_context_map()) {
-    if (browser_context) {
-      extensions::EventRouter::Get(browser_context.get())
+  for (auto* browser_context : ElectronBrowserContext::BrowserContexts()) {
+    extensions::EventRouter::Get(browser_context)
         ->BroadcastEvent(std::make_unique<extensions::Event>(
             histogram_value, event_name, args.Clone()));
   }
-  }
 }
 
 extensions::ExtensionCache*