Implement screen capture for android

content/browser/media/capture/desktop_capture_device.cc

 // Copyright (c) 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/desktop_capture_device.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread.h"
 #include "base/timer/timer.h"
 #include "content/browser/media/capture/desktop_capture_device_uma_types.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/desktop_media_id.h"
 #include "content/public/browser/power_save_blocker.h"
 #include "media/base/video_util.h"
+#if defined(OS_ANDROID)
+#include "media/screen_capture/android/screen_capturer_android.h"
+#endif
 #include "third_party/libyuv/include/libyuv/scale_argb.h"
 #include "third_party/webrtc/modules/desktop_capture/cropping_window_capturer.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_and_cursor_composer.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_capture_options.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_capturer.h"
 #include "third_party/webrtc/modules/desktop_capture/desktop_frame.h"
 #include "third_party/webrtc/modules/desktop_capture/mouse_cursor_monitor.h"
 #include "third_party/webrtc/modules/desktop_capture/screen_capturer.h"
 
 namespace content {
@@ skipping 145 matching lines @@
   capture_format_.pixel_format = media::PIXEL_FORMAT_ARGB;
 
   power_save_blocker_.reset(
       PowerSaveBlocker::Create(
           PowerSaveBlocker::kPowerSaveBlockPreventDisplaySleep,
           PowerSaveBlocker::kReasonOther,
           "DesktopCaptureDevice is running").release());
 
   desktop_capturer_->Start(this);
 
+#if defined(OS_ANDROID)
+  // For android, we don't use capture_timer_ to triger capturing. Instead,
+  // we use ImageReader.OnImageAvailableListener to listen when a screen frame
+  // available which is similar with VideoCapture

[miu, 2015/05/20 03:33:27]

What happens if the screen does not update for a long while?  Will this stop the
providing frames?

The comment here explains the issue that affects tab capture on all platforms,
and also desktop capture on ChromeOS:
https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/me...

+  return;
+#endif
+
   CaptureFrameAndScheduleNext();
 }
 
 void DesktopCaptureDevice::Core::SetNotificationWindowId(
     gfx::NativeViewId window_id) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(window_id);
   desktop_capturer_->SetExcludedWindow(window_id);
 }
 
 webrtc::SharedMemory*
 DesktopCaptureDevice::Core::CreateSharedMemory(size_t size) {
   return NULL;
 }
 
 void DesktopCaptureDevice::Core::OnCaptureCompleted(
     webrtc::DesktopFrame* frame) {
+#if !defined(OS_ANDROID)

[miu, 2015/05/20 03:33:27]

Why don't these statements apply to the android platform?  At the least, provide
a comment here.

   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(capture_in_progress_);
+#endif
 
   if (!first_capture_returned_) {
     first_capture_returned_ = true;
     if (capturer_type_ == DesktopMediaID::TYPE_SCREEN) {
       IncrementDesktopCaptureCounter(frame ? FIRST_SCREEN_CAPTURE_SUCCEEDED
                                            : FIRST_SCREEN_CAPTURE_FAILED);
     } else {
       IncrementDesktopCaptureCounter(frame ? FIRST_WINDOW_CAPTURE_SUCCEEDED
                                            : FIRST_WINDOW_CAPTURE_FAILED);
     }
@@ skipping 189 matching lines @@
   options.set_disable_effects(false);
 
 #if defined(OS_WIN)
       options.set_allow_use_magnification_api(true);
 #endif
 
   scoped_ptr<webrtc::DesktopCapturer> capturer;
 
   switch (source.type) {
     case DesktopMediaID::TYPE_SCREEN: {
+#if defined(OS_ANDROID)
+      scoped_ptr<webrtc::ScreenCapturer> screen_capturer(
+          new media::ScreenCapturerAndroid());
+#else
       scoped_ptr<webrtc::ScreenCapturer> screen_capturer(
           webrtc::ScreenCapturer::Create(options));
+#endif
       if (screen_capturer && screen_capturer->SelectScreen(source.id)) {
         capturer.reset(new webrtc::DesktopAndCursorComposer(
             screen_capturer.release(),
             webrtc::MouseCursorMonitor::CreateForScreen(options, source.id)));
         IncrementDesktopCaptureCounter(SCREEN_CAPTURER_CREATED);
       }
       break;
     }
 
     case DesktopMediaID::TYPE_WINDOW: {
@@ skipping 63 matching lines @@
 #else
   base::MessageLoop::Type thread_type = base::MessageLoop::TYPE_DEFAULT;
 #endif
 
   thread_.StartWithOptions(base::Thread::Options(thread_type, 0));
 
   core_.reset(new Core(thread_.task_runner(), capturer.Pass(), type));
 }
 
 }  // namespace content