feat: add client header to GoogleChat (#4884)

Added header per integration
[guidelines](https://ai.google.dev/gemini-api/docs/partner-integration).

<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Set the `x-goog-api-client` header for Google Chat requests to meet
Google partner integration guidelines. It identifies the client as
`browser-use/{version}` with a fallback of `unknown`.

- **New Features**
  - Add `x-goog-api-client` header with value `browser-use/{version}`.
- Normalize and merge `http_options`; always set/override the header in
client params.

- **Bug Fixes**
- Handle both `types.HttpOptions` and `types.HttpOptionsDict`,
preserving `timeout` and existing headers.
- Add tests covering `None`, Pydantic, and dict `http_options` to ensure
the header is set and prefixed with `browser-use/`.

<sup>Written for commit 115199d2ba.
Summary will update on new commits. <a
href="https://cubic.dev/pr/browser-use/browser-use/pull/4884?utm_source=github">Review
in cubic</a></sup>

<!-- End of auto-generated description by cubic. -->

browser_use/llm/google/chat.py

@@ -1,4 +1,5 @@
 import asyncio
+import importlib.metadata
 import json
 import logging
 import random
@@ -122,6 +123,33 @@ class ChatGoogle(BaseChatModel):
 		"""Get logger for this chat instance"""
 		return logging.getLogger(f'browser_use.llm.google.{self.model}')
 
+	def _get_http_options(self) -> dict[str, Any]:
+		"""Get http options with the default headers set."""
+		try:
+			bu_version = importlib.metadata.version('browser-use')
+		except importlib.metadata.PackageNotFoundError:
+			bu_version = 'unknown'
+
+		header_value = f'browser-use/{bu_version}'
+
+		http_opts: dict[str, Any] = {}
+
+		if self.http_options is not None:
+			if isinstance(self.http_options, types.HttpOptions):
+				http_opts = self.http_options.model_dump(exclude_unset=True)
+			elif isinstance(self.http_options, dict):
+				http_opts = dict(self.http_options)
+
+		headers: dict[str, str] = {}
+		existing_headers = http_opts.get('headers')
+		if isinstance(existing_headers, dict):
+			headers = {str(k): str(v) for k, v in existing_headers.items()}
+
+		headers['x-goog-api-client'] = header_value
+		http_opts['headers'] = headers
+
+		return http_opts
+
 	def _get_client_params(self) -> dict[str, Any]:
 		"""Prepare client parameters dictionary."""
 		# Define base client params
@@ -131,7 +159,7 @@ class ChatGoogle(BaseChatModel):
 			'credentials': self.credentials,
 			'project': self.project,
 			'location': self.location,
-			'http_options': self.http_options,
+			'http_options': self._get_http_options(),
 		}
 
 		# Create client_params dict with non-None values

tests/ci/models/test_llm_google.py

@@ -13,3 +13,59 @@ async def test_google_gemini_flash_latest(httpserver):
 		extra_kwargs={},
 		httpserver=httpserver,
 	)
+
+
+def test_x_goog_api_client_header_is_set():
+	"""Test that the x-goog-api-client header is correctly set in the HTTP options."""
+	chat = ChatGoogle(model='gemini-flash-latest', api_key='fake')
+
+	# Generate the params used for genai.Client
+	params = chat._get_client_params()
+
+	# Extract the header
+	http_options = params.get('http_options', {})
+	headers = http_options.get('headers', {})
+
+	assert 'x-goog-api-client' in headers, 'x-goog-api-client header missing'
+	assert 'browser-use/' in headers['x-goog-api-client'], 'browser-use not found in x-goog-api-client header'
+
+
+def test_x_goog_api_client_header_with_none_http_options():
+	"""Test setting header when http_options is None."""
+	chat = ChatGoogle(model='gemini-flash-latest', api_key='fake', http_options=None)
+	params = chat._get_client_params()
+	http_opts = params.get('http_options', {})
+	assert http_opts.get('headers', {}).get('x-goog-api-client', '').startswith('browser-use/')
+
+
+def test_x_goog_api_client_header_with_pydantic_http_options():
+	"""Test setting header when http_options is a types.HttpOptions Pydantic model."""
+	from google.genai import types
+
+	pydantic_opts = types.HttpOptions(timeout=30, headers={'custom-header': 'value'})
+	chat = ChatGoogle(model='gemini-flash-latest', api_key='fake', http_options=pydantic_opts)
+	params = chat._get_client_params()
+	http_opts = params.get('http_options', {})
+
+	# Verify it extracts and preserves timeout and custom-header
+	assert http_opts.get('timeout') == 30
+	assert http_opts.get('headers', {}).get('custom-header') == 'value'
+	assert http_opts.get('headers', {}).get('x-goog-api-client', '').startswith('browser-use/')
+
+
+def test_x_goog_api_client_header_with_dict_http_options():
+	"""Test setting header when http_options is a dictionary (types.HttpOptionsDict)."""
+	from google.genai import types
+
+	dict_opts: types.HttpOptionsDict = {
+		'timeout': 45,
+		'headers': {'another-header': 'another-value'},
+	}
+	chat = ChatGoogle(model='gemini-flash-latest', api_key='fake', http_options=dict_opts)
+	params = chat._get_client_params()
+	http_opts = params.get('http_options', {})
+
+	# Verify it preserves dictionary values and appends the tracking header
+	assert http_opts.get('timeout') == 45
+	assert http_opts.get('headers', {}).get('another-header') == 'another-value'
+	assert http_opts.get('headers', {}).get('x-goog-api-client', '').startswith('browser-use/')