media: Pare MCVD down to a minimal media::VideoDecoder

media/gpu/BUILD.gn

Index: media/gpu/BUILD.gn
diff --git a/media/gpu/BUILD.gn b/media/gpu/BUILD.gn
index b2963c3b95ad911349dca19009dd637c21d67b28..76fff7add14142728585bc553c2fcc5e772cab7c 100644
--- a/media/gpu/BUILD.gn
+++ b/media/gpu/BUILD.gn
@@ -8,6 +8,12 @@ import("//media/gpu/args.gni")
 import("//media/media_options.gni")
 import("//testing/test.gni")
 
+declare_args() {
+  # A temporary arg for building MCVD while it's being implemented.
+  # See http://crbug.com/660942
+  enable_media_codec_video_decoder = false
+}
+
 if (is_mac) {
   import("//build/config/mac/mac_sdk.gni")
 }
@@ -190,6 +196,13 @@ component("gpu") {
       ]
     }
 
+    if (enable_media_codec_video_decoder) {
+      sources += [
+        "android/media_codec_video_decoder.cc",
+        "android/media_codec_video_decoder.h",
+      ]
+    }
+
     # TODO(xhwang): This is needed for AVDA to access the CDM directly.
     # Remove this dependency after VDAs are also running as part of the mojo
     # media service. See http://crbug.com/522298
@@ -415,6 +428,9 @@ source_set("android_video_decode_accelerator_unittests") {
       "android_video_decode_accelerator_unittest.cc",
       "avda_codec_allocator_unittest.cc",
     ]
+    if (enable_media_codec_video_decoder) {
+      sources += [ "android/media_codec_video_decoder_unittest.cc" ]
+    }
     deps = [
       ":gpu",
       "//base/test:test_support",