feat: Add Vertex AI Agent Engine Sandbox integration for computer use

    Implement AgentEngineSandboxComputer, a BaseComputer implementation that
    uses Vertex AI Agent Engine Computer Use Sandbox as a remote browser
    environment. This enables computer-use agents to operate in secure,
    isolated cloud-based browser environments.

    Key features:
    - SandboxClient: Low-level CDP client using vertexai SDK send_command()
    - AgentEngineSandboxComputer: BaseComputer implementation with session
      state management for sandbox sharing across invocations
    - Support for both auto-provisioning and bring-your-own-sandbox (BYOS) modes
    - Automatic token refresh and retry logic for transient navigation errors
    - Fix wait_5_seconds adapter to properly pass tool_context

Co-authored-by: Xiang (Sean) Zhou <seanzhougoogle@google.com>
PiperOrigin-RevId: 900292803

Author: seanzhougoogle

src/google/adk/integrations/vmaas/__init__.py

@@ -0,0 +1,40 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Vertex AI Agent Engine Computer Use Sandbox integration.
+
+This module provides a BaseComputer implementation that uses Vertex AI
+Agent Engine Computer Use Sandbox as the remote browser environment.
+
+Example:
+  ```python
+  from google.adk.integrations.vmaas import AgentEngineSandboxComputer
+  from google.adk.tools.computer_use import ComputerUseToolset
+
+  computer = AgentEngineSandboxComputer(
+      project_id="my-project",
+      service_account_email="sa@my-project.iam.gserviceaccount.com",
+  )
+  toolset = ComputerUseToolset(computer=computer)
+  agent = Agent(tools=[toolset], ...)
+  ```
+"""
+
+from .sandbox_client import SandboxClient
+from .sandbox_computer import AgentEngineSandboxComputer
+
+__all__ = [
+    "AgentEngineSandboxComputer",
+    "SandboxClient",
+]