Remove Extraneous Backslash Introduced by clang-tidy in ScopedHandle

clang-tidy incorrectly processed some malformed gcc code in such a
way that it no longer compiles. This issue shouldn't recur as the
escaped backslash no longer exists in the updated version.

clang-tidy fixes made in r725741 / d8b73eb8f0321bf37931b69c66fdad82ff7063c5.

Fixed: 1076523
Change-Id: I706a516058ab426b4ba6c2f0d01d3ce11fb1a60a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2174910
Commit-Queue: Robert Liao <robliao@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Auto-Submit: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#764479}
diff --git a/base/win/scoped_handle.h b/base/win/scoped_handle.h
index 9055e3e..02c2533 100644
--- a/base/win/scoped_handle.h
+++ b/base/win/scoped_handle.h
@@ -20,7 +20,7 @@
 #define BASE_WIN_GET_CALLER _ReturnAddress()
 #elif defined(COMPILER_GCC)
 #define BASE_WIN_GET_CALLER \
-  __builtin_extract_return_addr(\ __builtin_return_address(0))
+  __builtin_extract_return_addr(__builtin_return_address(0))
 #endif
 
 namespace base {