Google's Chrome browser is now built using the Clang compiler on Windows. Previously built using the Microsoft C++ compiler, Google is now using the same compiler for Windows, macOS, Linux, and Android, and the switch makes Chrome arguably the first major software project to use Clang on Windows.
Chrome on macOS and Linux has long been built using the Clang compiler and the LLVM toolchain. The open source compiler is the compiler of choice on macOS, making it the natural option there, and it's also a first-class choice for Linux; though the venerable GCC is still the primary compiler choice on Linux, by using Clang instead, Google ensured that it has only one set of compiler quirks and oddities to work with rather than two.
But Chrome on Windows has instead used Microsoft's Visual C++ compiler. The Visual C++ compiler is the best-supported, most widely used compiler on Windows and, critically, is the compiler with the best support for Windows' wide range of debugging and diagnostic tools. The Visual Studio debugger is widely loved by the C++ community, and other tools, such as the WinDbg debugger (often used for analyzing crash dumps), are core parts of the Windows developer experience.