docs: create documentation for browser api (#30071)

* docs: create documentation for browser api

* docs: add cpp theme

docs/tutorial/creating-api.md

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+# Creating an Electron Browser Module API
+
+Welcome to the Electron API guide! If you are unfamiliar with creating electron APIs within the `browser` module, this guide serves as a checklist for some of the necessary steps that you will need to implement.
+
+This is not a comprehensive end-all guide to creating an Electron Browser API, rather an outline documenting some of the more unintuitive steps.
+
+## Adding Your Files To Electron's Project Configuration
+
+Electron uses [GN](https://gn.googlesource.com/gn) as a meta build system to generate files for its compiler, [Ninja](https://ninja-build.org/). This means that in order to tell Electron to compile your code, we have to add your API's code and header file names  into [`filenames.gni`](https://github.com/electron/electron/blob/main/filenames.gni).
+
+You will need to append your api file names alphabetically into the appropriate files like so:
+
+```cpp
+lib_sources = [
+    "path/to/api/api_name.cc",
+    "path/to/api/api_name.h",
+]
+
+lib_sources_mac = [
+    "path/to/api/api_name_mac.h",
+    "path/to/api/api_name_mac.mm",
+]
+
+lib_sources_win = [
+    "path/to/api/api_name_win.cc",
+    "path/to/api/api_name_win.h",
+]
+
+lib_sources_linux = [
+    "path/to/api/api_name_linux.cc",
+    "path/to/api/api_name_linux.h",
+]
+```
+
+Note that the Windows, MacOS and Linux array additions are optional and should only be added if your API has specific platform implementations.
+
+## Create API Documentation
+
+Type definitions are generated by Electron using [`docs-parser`](https://github.com/electron/docs-parser) and [`typescript-definitions`](https://github.com/electron/typescript-definitions). This step is necessary to ensure consistency across Electron's API documentation. This means that for your API type definition to appear in the `electron.d.ts` file, we must create a `.md` file. Examples can be found in [this folder](https://github.com/electron/electron/tree/main/docs/api).
+
+## Setting Up `ObjectTemplateBuilder` and `Wrappable`
+
+Electron constructs its modules using [`object_template_builder`](https://www.electronjs.org/blog/from-native-to-js#mateobjecttemplatebuilder).
+
+[`wrappable`](https://chromium.googlesource.com/chromium/src/+/refs/heads/main/gin/wrappable.h) is a base class for C++ objects that have corresponding v8 wrapper objects.
+
+Here is a basic example of code that you may need to add, in order to incorporate `object_template_builder` and `wrappable` into your API. For further reference, you can find more implementations [here](https://github.com/electron/electron/tree/main/shell/browser/api).
+
+In your `api_name.h` file:
+
+```cpp
+
+#ifndef SHELL_BROWSER_API_ELECTRON_API_{API_NAME}_H_
+#define SHELL_BROWSER_API_ELECTRON_API_{API_NAME}_H_
+
+#include "gin/handle.h"
+#include "gin/wrappable.h"
+
+namespace electron {
+
+namespace api {
+
+class ApiName : public gin::Wrappable<ApiName>  {
+ public:
+  static gin::Handle<ApiName> Create(v8::Isolate* isolate);
+
+  // gin::Wrappable
+  static gin::WrapperInfo kWrapperInfo;
+  gin::ObjectTemplateBuilder GetObjectTemplateBuilder(
+      v8::Isolate* isolate) override;
+  const char* GetTypeName() override;
+} // namespace api
+} // namespace electron
+```
+
+In your `api_name.cc` file:
+
+```cpp
+#include "shell/browser/api/electron_api_safe_storage.h"
+
+#include "shell/browser/browser.h"
+#include "shell/common/gin_converters/base_converter.h"
+#include "shell/common/gin_converters/callback_converter.h"
+#include "shell/common/gin_helper/dictionary.h"
+#include "shell/common/gin_helper/object_template_builder.h"
+#include "shell/common/node_includes.h"
+#include "shell/common/platform_util.h"
+
+namespace electron {
+
+namespace api {
+
+gin::WrapperInfo ApiName::kWrapperInfo = {gin::kEmbedderNativeGin};
+
+gin::ObjectTemplateBuilder ApiName::GetObjectTemplateBuilder(
+    v8::Isolate* isolate) {
+  return gin::ObjectTemplateBuilder(isolate)
+      .SetMethod("methodName", &ApiName::methodName);
+}
+
+const char* ApiName::GetTypeName() {
+  return "ApiName";
+}
+
+// static
+gin::Handle<ApiName> ApiName::Create(v8::Isolate* isolate) {
+  return gin::CreateHandle(isolate, new ApiName());
+}
+
+} // namespace api
+
+} // namespace electron
+
+namespace {
+
+void Initialize(v8::Local<v8::Object> exports,
+                v8::Local<v8::Value> unused,
+                v8::Local<v8::Context> context,
+                void* priv) {
+  v8::Isolate* isolate = context->GetIsolate();
+  gin_helper::Dictionary dict(isolate, exports);
+  dict.Set("apiName", electron::api::ApiName::Create(isolate));
+}
+
+}  // namespace
+```
+
+## Link Your Electron API With Node
+
+To learn about how Electron links with Node, [click here.](https://www.electronjs.org/blog/electron-internals-using-node-as-a-library#link-node-with-electron)
+
+In the [`internal-ambient.d.ts`](https://github.com/electron/electron/blob/main/typings/internal-ambient.d.ts) file:
+
+We need to append a new property onto the `Process` interface found in this file like so:
+
+```ts
+interface Process {
+    _linkedBinding(name: 'electron_browser_{api_name}', Electron.ApiName);
+}
+```
+
+At the very bottom of your `api_name.cc` file:
+
+```cpp
+NODE_LINKED_MODULE_CONTEXT_AWARE(electron_browser_{api_name},Initialize)
+```
+
+In your [`shell/common/node_bindings.cc`](https://github.com/electron/electron/blob/main/shell/common/node_bindings.cc) file:
+
+Add your node binding name to Electron's built-in modules.
+
+```cpp
+#define ELECTRON_BUILTIN_MODULES(V)      \
+  V(electron_browser_{api_name})
+```
+
+## Expose Your API to TypeScript
+
+### Export Your API as a module
+
+We will need to create a new TypeScript file in the path that follows:
+
+`"lib/browser/api/{electron_browser_{api_name}}.ts"`
+
+An example of the contents of this file can be found [here](https://github.com/electron/electron/blob/main/lib/browser/api/native-image.ts).
+
+### Expose Your module to TypeScript
+
+Add your module to the module list found at `"lib/browser/api/module-list.ts"` like so:
+
+```typescript
+export const browserModuleList: ElectronInternal.ModuleEntry[] = [
+  { name: 'apiName', loader: () => require('./api-name') },
+];
+```