Rotate frames correctly for back camera

media/capture/video/linux/video_capture_device_linux.cc

Index: media/capture/video/linux/video_capture_device_linux.cc
diff --git a/media/capture/video/linux/video_capture_device_linux.cc b/media/capture/video/linux/video_capture_device_linux.cc
index a1b2855055e853b5e1d9210f5da139f8740ef7ec..2d6d5d3231db8284751cf1a559c1fad0ef753e2b 100644
--- a/media/capture/video/linux/video_capture_device_linux.cc
+++ b/media/capture/video/linux/video_capture_device_linux.cc
@@ -11,6 +11,7 @@
 #include "base/bind.h"
 #include "base/single_thread_task_runner.h"
 #include "build/build_config.h"
+#include "media/capture/video/linux/camera_characteristics.h"
 #include "media/capture/video/linux/v4l2_capture_delegate.h"
 
 #if defined(OS_OPENBSD)
@@ -38,7 +39,8 @@ std::list<uint32_t> VideoCaptureDeviceLinux::GetListOfUsableFourCCs(
 VideoCaptureDeviceLinux::VideoCaptureDeviceLinux(
     const VideoCaptureDeviceDescriptor& device_descriptor)
     : v4l2_thread_("V4L2CaptureThread"),
-      device_descriptor_(device_descriptor) {}
+      device_descriptor_(device_descriptor),
+      is_back_camera_(GetCameraFacing(device_descriptor)) {}
 
 VideoCaptureDeviceLinux::~VideoCaptureDeviceLinux() {
   // Check if the thread is running.
@@ -63,6 +65,7 @@ void VideoCaptureDeviceLinux::AllocateAndStart(
     client->OnError(FROM_HERE, "Failed to create VideoCaptureDelegate");
     return;
   }
+  client->SetCameraFacing(is_back_camera_);
   v4l2_thread_.task_runner()->PostTask(
       FROM_HERE,
       base::Bind(&V4L2CaptureDelegate::AllocateAndStart, capture_impl_,
@@ -133,4 +136,10 @@ int VideoCaptureDeviceLinux::TranslatePowerLineFrequencyToV4L2(
   }
 }
 
+bool VideoCaptureDeviceLinux::GetCameraFacing(

[wuchengli, 2016/11/16 12:15:19]

This is just two lines of code. We don't need a function for this.

[shenghao, 2016/11/17 08:41:44]

But I need it to be a function so that I can initialize is_back_camera_ in the
initializer list.

[wuchengli, 2016/11/17 09:26:04]

Why not initialize it in the constructor?

[shenghao, 2016/11/17 10:15:54]

Done.

+    const VideoCaptureDeviceDescriptor& descriptor) {
+  CameraCharacteristics characteristics;
+  return characteristics.GetCameraFacing(descriptor.model_id) == 1;

[wuchengli, 2016/11/16 12:15:19]

Need a constant for 0 and 1.

[shenghao, 2016/11/17 08:41:44]

Done.

+}
+
 }  // namespace media