[dotnet] Add nullability to Chromium configuration types

[RenderMichael]

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Add nullability to Chromium configuration types

Motivation and Context

Contributes to #14640

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

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PR Type

Enhancement

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Description

• Enabled nullable reference types in Chromium-related classes.

• Simplified property declarations and removed backing fields.

• Improved exception handling and validation logic.

• Enhanced code readability and maintainability.

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Changes walkthrough 📝

Relevant files

Enhancement

ChromiumAndroidOptions.cs Refactored ChromiumAndroidOptions with nullable types        dotnet/src/webdriver/Chromium/ChromiumAndroidOptions.cs Enabled nullable reference types. Simplified property declarations by removing backing fields. Made AndroidProcess nullable. +4/-13    ChromiumMobileEmulationDeviceSettings.cs Refactored ChromiumMobileEmulationDeviceSettings with nullable types dotnet/src/webdriver/Chromium/ChromiumMobileEmulationDeviceSettings.cs Enabled nullable reference types. Simplified property declarations by removing backing fields. Made UserAgent nullable. Set default value for EnableTouchEvents. +9/-33    ChromiumNetworkConditions.cs Refactored ChromiumNetworkConditions with nullable types  dotnet/src/webdriver/Chromium/ChromiumNetworkConditions.cs Enabled nullable reference types. Simplified property declarations by removing backing fields. Improved exception handling for throughput validation. Refactored dictionary parsing logic. +18/-31  ChromiumPerformanceLoggingPreferences.cs Refactored ChromiumPerformanceLoggingPreferences with nullable types dotnet/src/webdriver/Chromium/ChromiumPerformanceLoggingPreferences.cs Enabled nullable reference types. Simplified property declarations by removing backing fields. Improved exception handling for invalid arguments. Refactored tracing categories logic. +14/-33

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PR Reviewer Guide 🔍

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⏱️ Estimated effort to review: 2 🔵🔵⚪⚪⚪

🧪 No relevant tests

🔒 No security concerns identified

⚡ Recommended focus areas for review Error Message The error message for negative download throughput was fixed from "Downlod" to "Download", but the error handling for upload throughput is missing a similar error message. set { if (value < 0) { Constructor Issue The parameterized constructor is missing the initialization code block, which could lead to the UserAgent property not being set properly. public ChromiumMobileEmulationDeviceSettings(string? userAgent) { this.UserAgent = userAgent; }

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PR Code Suggestions ✨

Explore these optional code suggestions:

Category	Suggestion	Score
General	Standardize exception types for validation Use consistent exception types for throughput validation. Currently using WebDriverException for download but ArgumentOutOfRangeException for bidirectional throughput. Should standardize on ArgumentOutOfRangeException for all throughput validations. dotnet/src/webdriver/Chromium/ChromiumNetworkConditions.cs [59] -throw new WebDriverException("Download throughput cannot be negative."); +throw new ArgumentOutOfRangeException(nameof(value), "Download throughput cannot be negative."); Apply this suggestion Suggestion importance[1-10]: 7 Why: Important consistency improvement that aligns with .NET best practices by using ArgumentOutOfRangeException for parameter validation across the codebase.	7
	Fix typo in error message Fix typo in error message for negative download throughput. The current message has a spelling error ("Downlod" instead of "Download"). dotnet/src/webdriver/Chromium/ChromiumNetworkConditions.cs [59] -throw new WebDriverException("Downlod throughput cannot be negative."); +throw new WebDriverException("Download throughput cannot be negative."); Apply this suggestion Suggestion importance[1-10]: 4 Why: Fixes a minor spelling error in an error message that could affect user experience and code professionalism, though not impacting functionality.	4
Learned best practice	Include actual values in exception messages to improve debugging experience The exception message for negative throughput values should include the actual invalid value to help with debugging. Update the validation check in DownloadThroughput and UploadThroughput properties to include the invalid value in the error message. dotnet/src/webdriver/Chromium/ChromiumNetworkConditions.cs [59] -throw new WebDriverException("Download throughput cannot be negative."); +throw new WebDriverException($"Download throughput cannot be negative. Provided value: {value}"); Apply this suggestion	6