Disabled SaveAsMHTML on Windows

TBR=benwells@chromium.org

Bug: 1017305
Change-Id: I076e6b428335ad9756dbba32fed98a001d676a25
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1899884Reviewed-by: Andy Paicu <andypaicu@chromium.org>
Commit-Queue: Andy Paicu <andypaicu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712938}

chrome/browser/extensions/api/page_capture/page_capture_apitest.cc

@@ -77,7 +77,8 @@ class PageCaptureSaveAsMHTMLDelegate
 
 // TODO(crbug.com/961017): Fix memory leaks in tests and re-enable on LSAN.
 // Also flaky-failing on slow (debug) bots: https://crbug.com/1017305
-#if defined(LEAK_SANITIZER) || !defined(NDEBUG) || defined(ADDRESS_SANITIZER)
+#if defined(LEAK_SANITIZER) || !defined(NDEBUG) || \
+    defined(ADDRESS_SANITIZER) || defined(OS_WIN)
 #define MAYBE_SaveAsMHTML DISABLED_SaveAsMHTML
 #else
 #define MAYBE_SaveAsMHTML SaveAsMHTML