Initialize Cast Media for cast_media_unittests

This allows removal of the lazy initialisation workaround recently
added to vendor media implementation.

BUG=

Review URL: https://codereview.chromium.org/1137183003

Cr-Commit-Position: refs/heads/master@{#330136}

chromecast/media/cma/backend/audio_video_pipeline_device_unittest.cc

@@ -6,6 +6,7 @@
 
 #include "base/basictypes.h"
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/logging.h"
@@ -28,6 +29,7 @@
 #include "chromecast/media/cma/base/decoder_config_adapter.h"
 #include "chromecast/media/cma/test/frame_segmenter_for_test.h"
 #include "chromecast/media/cma/test/media_component_device_feeder_for_test.h"
+#include "chromecast/public/cast_media_shlib.h"
 #include "chromecast/public/media/decoder_config.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/buffers.h"
@@ -71,6 +73,15 @@ class AudioVideoPipelineDeviceTest : public testing::Test {
   AudioVideoPipelineDeviceTest();
   ~AudioVideoPipelineDeviceTest() override;
 
+  void SetUp() override {
+    CastMediaShlib::Initialize(
+        base::CommandLine::ForCurrentProcess()->argv());
+  }
+
+  void TearDown() override {
+    CastMediaShlib::Finalize();
+  }
+
   void ConfigureForFile(std::string filename);
   void ConfigureForAudioOnly(std::string filename);
   void ConfigureForVideoOnly(std::string filename, bool raw_h264);

chromecast/public/cast_media_shlib.h

@@ -13,15 +13,24 @@
 namespace chromecast {
 namespace media {
 
+// Provides access to platform-specific media systems and hardware resources.
+// In cast_shell, all usage is from the browser process.  An implementation is
+// assumed to be in an uninitialized state initially.  When uninitialized, no
+// API calls will be made except for Initialize, which brings the implementation
+// into an initialized state.  A call to Finalize returns the implementation to
+// its uninitialized state.  The implementation must support multiple
+// transitions between these states, to support resource grant/revoke events and
+// also to allow multiple unit tests to bring up the media systems in isolation
+// from other tests.
 class CHROMECAST_EXPORT CastMediaShlib {
  public:
-  // Performs platform-specific one-time initialization for media systems and
-  // hardware resources. Called at startup in browser process before main
-  // message loop begins.
+  // Initializes platform-specific media systems.  Only called when in an
+  // uninitialized state.
   static void Initialize(const std::vector<std::string>& argv);
 
-  // Performs platform-specific one-time teardown of media systems and hardware
-  // resources. Called at browser process exit.
+  // Tears down platform-specific media systems and returns to the uninitialized
+  // state.  The implementation must release all media-related hardware
+  // resources.
   static void Finalize();
 };