[base][win] Better check in SetSystemPagesAccessInternal

I made improvements to https://crrev.com/c/1336130 but I forgot
to save them. With this CL we should get more information about
crashes on Windows.

R=haraken@chromium.org

Change-Id: Ie1cea16e9e6574cb9028a165d8bf5a68465bd965
Reviewed-on: https://chromium-review.googlesource.com/c/1338099Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609240}

base/allocator/partition_allocator/page_allocator_internals_win.h

@@ -80,10 +80,18 @@ void SetSystemPagesAccessInternal(
     size_t length,
     PageAccessibilityConfiguration accessibility) {
   if (accessibility == PageInaccessible) {
-    CHECK_NE(0, VirtualFree(address, length, MEM_DECOMMIT));
+    if (!VirtualFree(address, length, MEM_DECOMMIT)) {
+      // We check `GetLastError` for `ERROR_SUCCESS` here so that in a crash
+      // report we get the error number.
+      CHECK_EQ(static_cast<uint32_t>(ERROR_SUCCESS), GetLastError());
+    }
   } else {
-    CHECK_NE(nullptr, VirtualAlloc(address, length, MEM_COMMIT,
-                                   GetAccessFlags(accessibility)));
+    if (!VirtualAlloc(address, length, MEM_COMMIT,
+                      GetAccessFlags(accessibility))) {
+      // We check `GetLastError` for `ERROR_SUCCESS` here so that in a crash
+      // report we get the error number.
+      CHECK_EQ(static_cast<uint32_t>(ERROR_SUCCESS), GetLastError());
+    }
   }
 }