Remove implicit HANDLE conversions from win8.

BUG=416722
R=ananta@chromium.org

Review URL: https://codereview.chromium.org/599173003

Cr-Commit-Position: refs/heads/master@{#297004}

win8/delegate_execute/delegate_execute.cc

@@ -97,7 +97,7 @@ int RelaunchChrome(const DelegateExecuteOperation& operation) {
   ScopedHandle mutex(OpenMutexW(SYNCHRONIZE, FALSE, operation.mutex().c_str()));
   if (mutex.IsValid()) {
     const int kWaitSeconds = 5;
-    DWORD result = ::WaitForSingleObject(mutex, kWaitSeconds * 1000);
+    DWORD result = ::WaitForSingleObject(mutex.Get(), kWaitSeconds * 1000);
     if (result == WAIT_ABANDONED) {
       // This is the normal case. Chrome exits and windows marks the mutex as
       // abandoned.