Relocate SurfaceTexture usage from AVDA GLImage into shared state.

media/gpu/avda_shared_state.cc

Index: media/gpu/avda_shared_state.cc
diff --git a/media/gpu/avda_shared_state.cc b/media/gpu/avda_shared_state.cc
index 12b25256fabf2e4ac2a9c84ec0ef1dcea54730ea..3fe7e0d54169220d99a1620ab809ec146992e678 100644
--- a/media/gpu/avda_shared_state.cc
+++ b/media/gpu/avda_shared_state.cc
@@ -16,7 +16,14 @@ namespace media {
 AVDASharedState::AVDASharedState()
     : surface_texture_service_id_(0),
       frame_available_event_(base::WaitableEvent::ResetPolicy::AUTOMATIC,
-                             base::WaitableEvent::InitialState::NOT_SIGNALED) {}
+                             base::WaitableEvent::InitialState::NOT_SIGNALED),
+
+      gl_matrix_{
+          1, 0, 1, 0,  // Default to a sane guess just in case we can't get the

[liberato (no reviews please), 2016/10/05 15:35:17]

methinks that the 1 in the third column should be zero.  the 1 in the fourth row
in the original is added by the y flip to translate along y.

i'll cq this and land a follow-up.

+          0, 1, 0, 0,  // matrix on the first call. Will be Y-flipped later.
+          0, 0, 1, 0,  //
+          0, 0, 0, 1,  // Comment preserves 4x4 formatting.
+      } {}
 
 AVDASharedState::~AVDASharedState() {
   if (!surface_texture_service_id_)
@@ -107,4 +114,14 @@ void AVDASharedState::RenderCodecBufferToSurfaceTexture(
   release_time_ = base::TimeTicks::Now();
 }
 
+void AVDASharedState::UpdateTexImage() {
+  surface_texture_->UpdateTexImage();
+  // Helpfully, this is already column major.
+  surface_texture_->GetTransformMatrix(gl_matrix_);
+}
+
+void AVDASharedState::GetTransformMatrix(float matrix[16]) const {
+  memcpy(matrix, gl_matrix_, sizeof(gl_matrix_));
+}
+
 }  // namespace media