components/arc: Determine the secure playback by ProtectedBufferManager

Originally, we rely on ARC side to determine if the playback is secure
or normal by passing a flag at initialization. But we could get the
information from the input buffer directly.

In this CL, we determine if the playback is secure by querying
ProtectedBufferManager with the first input buffer. If we can get the
corresponding protected buffer, then we consider the playback as
secure. Otherwise, we consider it as normal playback.

BUG=b:153608694
TEST=play sintel at Google Play Movie on rammus-arc-r

Change-Id: I0e30ca169a36223b9d82854f3382303a68c1ba3a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2377040
Commit-Queue: Chih-Yu Huang <akahuang@chromium.org>
Reviewed-by: Alexandre Courbot <acourbot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804135}

components/arc/video_accelerator/gpu_arc_video_decode_accelerator.cc

@@ -7,7 +7,9 @@
 #include <utility>
 
 #include "base/bind.h"
+#include "base/files/scoped_file.h"
 #include "base/metrics/histogram_macros.h"
+#include "base/posix/eintr_wrapper.h"
 #include "build/build_config.h"
 #include "components/arc/video_accelerator/arc_video_accelerator_util.h"
 #include "components/arc/video_accelerator/protected_buffer_manager.h"
@@ -312,11 +314,6 @@ GpuArcVideoDecodeAccelerator::InitializeTask(
     return mojom::VideoDecodeAccelerator::Result::INSUFFICIENT_RESOURCES;
   }
 
-  if (config->secure_mode && !protected_buffer_manager_) {
-    VLOGF(1) << "Secure mode unsupported";
-    return mojom::VideoDecodeAccelerator::Result::PLATFORM_FAILURE;
-  }
-
   media::VideoDecodeAccelerator::Config vda_config(config->profile);
   vda_config.output_mode =
       media::VideoDecodeAccelerator::Config::OutputMode::IMPORT;
@@ -331,7 +328,7 @@ GpuArcVideoDecodeAccelerator::InitializeTask(
   }
 
   client_count_++;
-  secure_mode_ = config->secure_mode;
+  secure_mode_ = base::nullopt;
   error_state_ = false;
   pending_requests_ = {};
   pending_flush_callbacks_ = {};
@@ -359,8 +356,31 @@ void GpuArcVideoDecodeAccelerator::Decode(
   }
   DVLOGF(4) << "fd=" << handle_fd.get();
 
+  // If this is the first input buffer, determine if the playback is secure by
+  // querying ProtectedBufferManager. If we can get the corresponding protected
+  // buffer, then we consider the playback as secure. Otherwise, we consider it
+  // as a normal playback.
+  if (!secure_mode_.has_value()) {
+    if (!protected_buffer_manager_) {
+      DVLOGF(3) << "ProtectedBufferManager is null, treat as normal playback";
+      secure_mode_ = false;
+    } else {
+      base::ScopedFD dup_fd(HANDLE_EINTR(dup(handle_fd.get())));
+      if (!dup_fd.is_valid()) {
+        client_->NotifyError(
+            mojom::VideoDecodeAccelerator::Result::INVALID_ARGUMENT);
+        return;
+      }
+
+      secure_mode_ = protected_buffer_manager_
+                         ->GetProtectedSharedMemoryRegionFor(std::move(dup_fd))
+                         .IsValid();
+      VLOGF(2) << "First input buffer is secure buffer? " << *secure_mode_;
+    }
+  }
+
   base::subtle::PlatformSharedMemoryRegion shm_region;
-  if (secure_mode_) {
+  if (*secure_mode_) {
     // Use protected shared memory associated with the given file descriptor.
     shm_region = protected_buffer_manager_->GetProtectedSharedMemoryRegionFor(
         std::move(handle_fd));
@@ -473,7 +493,8 @@ void GpuArcVideoDecodeAccelerator::ImportBufferForPicture(
 
   gfx::GpuMemoryBufferHandle gmb_handle;
   gmb_handle.type = gfx::NATIVE_PIXMAP;
-  if (secure_mode_) {
+  DCHECK(!secure_mode_.has_value());
+  if (*secure_mode_) {
     // Get protected output buffer associated with |handle_fd|.
     // Duplicating handle here is needed as ownership of passed fd is
     // transferred to AllocateProtectedNativePixmap().

components/arc/video_accelerator/gpu_arc_video_decode_accelerator.h

@@ -12,6 +12,7 @@
 
 #include "base/callback_forward.h"
 #include "base/files/scoped_file.h"
+#include "base/optional.h"
 #include "base/threading/thread_checker.h"
 #include "components/arc/mojom/video_decode_accelerator.mojom.h"
 #include "gpu/config/gpu_preferences.h"
@@ -150,7 +151,7 @@ class GpuArcVideoDecodeAccelerator
 
   size_t protected_input_buffer_count_ = 0;
 
-  bool secure_mode_ = false;
+  base::Optional<bool> secure_mode_ = base::nullopt;
   size_t output_buffer_count_ = 0;
   bool assign_picture_buffers_called_ = false;