Screen Video Capture: Implement suspend optimization.

content/browser/media/capture/aura_window_capture_machine.cc

 // Copyright 2013 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/media/capture/aura_window_capture_machine.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/logging.h"
@@ skipping 20 matching lines @@
 #include "ui/compositor/compositor.h"
 #include "ui/compositor/dip_util.h"
 #include "ui/compositor/layer.h"
 #include "ui/wm/public/activation_client.h"
 
 namespace content {
 
 AuraWindowCaptureMachine::AuraWindowCaptureMachine()
     : desktop_window_(NULL),
       screen_capture_(false),
+      frame_capture_active_(true),
       weak_factory_(this) {}
 
 AuraWindowCaptureMachine::~AuraWindowCaptureMachine() {}
 
 void AuraWindowCaptureMachine::Start(
   const scoped_refptr<media::ThreadSafeCaptureOracle>& oracle_proxy,
   const media::VideoCaptureParams& params,
   const base::Callback<void(bool)> callback) {
   // Starts the capture machine asynchronously.
   BrowserThread::PostTaskAndReplyWithResult(
@@ skipping 36 matching lines @@
 
   power_save_blocker_.reset(new device::PowerSaveBlocker(
       device::PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep,
       device::PowerSaveBlocker::kReasonOther, "DesktopCaptureDevice is running",
       BrowserThread::GetTaskRunnerForThread(BrowserThread::UI),
       BrowserThread::GetTaskRunnerForThread(BrowserThread::FILE)));
 
   return true;
 }
 
+void AuraWindowCaptureMachine::Suspend() {
+  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                          base::Bind(&AuraWindowCaptureMachine::InternalSuspend,
+                                     base::Unretained(this)));
+}
+
+void AuraWindowCaptureMachine::InternalSuspend() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DVLOG(1) << "Suspending frame capture and delivery.";
+  frame_capture_active_ = false;
+}
+
+void AuraWindowCaptureMachine::Resume() {
+  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                          base::Bind(&AuraWindowCaptureMachine::InternalResume,
+                                     base::Unretained(this)));
+}
+
+void AuraWindowCaptureMachine::InternalResume() {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  DVLOG(1) << "Resuming frame capture and delivery.";
+  frame_capture_active_ = true;
+}
+
 void AuraWindowCaptureMachine::Stop(const base::Closure& callback) {
   // Stops the capture machine asynchronously.
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE, base::Bind(
           &AuraWindowCaptureMachine::InternalStop,
           base::Unretained(this),
           callback));
 }
 
 void AuraWindowCaptureMachine::InternalStop(const base::Closure& callback) {
@@ skipping 294 matching lines @@
   // this is the only reliable way to ensure all screen changes are captured, as
   // of this writing.
   // http://crbug.com/600031
   //
   // TODO(miu): Need a better observer callback interface from the compositor
   // for this use case. The solution here will always capture frames at the
   // maximum framerate, which means CPU/GPU is being wasted on redundant
   // captures and quality/smoothness of animating content will suffer
   // significantly.
   // http://crbug.com/492839
-  Capture(timestamp);
+  if (frame_capture_active_)
+    Capture(timestamp);
 }
 
 void AuraWindowCaptureMachine::OnCompositingShuttingDown(
     ui::Compositor* compositor) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   compositor->RemoveAnimationObserver(this);
 }
 
 }  // namespace content