Keep screen on when there is an active WebRTC session on Android.

content/browser/power_save_blocker_android.cc

 // Copyright (c) 2012 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 "content/browser/power_save_blocker_impl.h"
 
 #include "base/logging.h"
+#include "content/browser/android/content_video_view.h"
+#include "content/public/browser/browser_thread.h"
 
 namespace content {
+namespace {
+int g_blocker_count;
+}  // namespace
 
 class PowerSaveBlockerImpl::Delegate
-    : public base::RefCounted<PowerSaveBlockerImpl::Delegate> {
+    : public base::RefCountedThreadSafe<PowerSaveBlockerImpl::Delegate> {
+ public:
+  Delegate(PowerSaveBlockerType type, const std::string& reason)
+      : type_(type), reason_(reason) {}
+
+  // Does the actual work to apply or remove the desired power save block.
+  void ApplyBlock();
+  void RemoveBlock();
+
  private:
-  friend class base::RefCounted<Delegate>;
+  friend class base::RefCountedThreadSafe<Delegate>;
   ~Delegate() {}
+
+  PowerSaveBlockerType type_;
+  const std::string reason_;
+
+  DISALLOW_COPY_AND_ASSIGN(Delegate);
 };
 
+void PowerSaveBlockerImpl::Delegate::ApplyBlock() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (type_ == kPowerSaveBlockPreventDisplaySleep) {
+    if (g_blocker_count == 0) {
+      ContentVideoView::KeepScreenOn(true);
+    }
+    ++g_blocker_count;
+  }
+}
+
+void PowerSaveBlockerImpl::Delegate::RemoveBlock() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  if (type_ == kPowerSaveBlockPreventDisplaySleep) {
+    --g_blocker_count;
+    if (g_blocker_count == 0) {
+      ContentVideoView::KeepScreenOn(false);
+    }
+  }
+}
+
 PowerSaveBlockerImpl::PowerSaveBlockerImpl(PowerSaveBlockerType type,
-                                           const std::string& reason) {
-  // TODO(wangxianzhu): Implement it.
-  // This may be called on any thread.
-  NOTIMPLEMENTED();
+                                           const std::string& reason)
+    : delegate_(new Delegate(type, reason)) {
+  BrowserThread::PostTask(

[mkosiba (inactive), 2013/05/17 09:34:47]

rather than spamming the UI thread maybe make the increment and decrement atomic
and post to the UI thread only if you need to call KeepScreenOn.

also, you can check the type_ before posting.

[wjia(left Chromium), 2013/05/17 18:04:43]

Done.

+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&Delegate::ApplyBlock, delegate_));
 }
 
 PowerSaveBlockerImpl::~PowerSaveBlockerImpl() {
+  BrowserThread::PostTask(
+      BrowserThread::UI, FROM_HERE,
+      base::Bind(&Delegate::RemoveBlock, delegate_));
 }
 
 }  // namespace content