Disable system suspend while downloading files on win32....

chrome/browser/power_save_blocker_common.cc

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/power_save_blocker.h"
+#include "chrome/browser/chrome_thread.h"
+
+// Accessed only from the UI thread.
+int PowerSaveBlocker::blocker_count_ = 0;
+
+PowerSaveBlocker::PowerSaveBlocker(bool enable) : enabled_(false) {
+  if (enable)
+    Enable();
+}
+
+PowerSaveBlocker::~PowerSaveBlocker(void) {
+  Disable();
+}
+
+void PowerSaveBlocker::Enable() {
+  if (enabled_)
+    return;
+
+  enabled_ = true;
+  PostAdjustBlockCount(1);
+}
+
+void PowerSaveBlocker::Disable() {
+  if (!enabled_)
+    return;
+
+  enabled_ = false;
+  PostAdjustBlockCount(-1);
+}
+
+
+void PowerSaveBlocker::PostAdjustBlockCount(int delta) {
+  MessageLoop *ml = ChromeThread::GetMessageLoop(ChromeThread::UI);
+
+  ml->PostTask(FROM_HERE,
+      NewRunnableFunction(&PowerSaveBlocker::AdjustBlockCount, delta));
+}
+
+// Called only from UI thread.
+void PowerSaveBlocker::AdjustBlockCount(int delta) {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+
+  bool was_blocking = (blocker_count_ != 0);
+
+  blocker_count_ += delta;
+
+  bool is_blocking = (blocker_count_ != 0);
+
+  DCHECK_GE(blocker_count_, 0);
+
+  if (is_blocking != was_blocking)
+    ApplyBlock(is_blocking);
+}