Don't use AVDA for <360p VPx content.

Power measurements on a nexus 5 show that there's very little
difference below 360p between hardware and libvpx decoding.  This CL
switches to libvpx decoding for <360p, even if it could be hardware
accelerated by AVDA.

This saves a hardware codec instance, and avoids potential stability
issues with lots of MediaCodecs in use at once.

BUG=647259, 642948
TEST=manually checked 240p and 360p.

Review-Url: https://codereview.chromium.org/2334223009
Cr-Commit-Position: refs/heads/master@{#418964}

media/gpu/android_video_decode_accelerator.cc

@@ -1571,7 +1571,9 @@ AndroidVideoDecodeAccelerator::GetCapabilities(
       MediaCodecUtil::IsVp8DecoderAvailable()) {
     SupportedProfile profile;
     profile.profile = VP8PROFILE_ANY;
-    profile.min_resolution.SetSize(0, 0);
+    // Since there is little to no power benefit below 360p, don't advertise
+    // support for it.  Let libvpx decode it, and save a MediaCodec instance.
+    profile.min_resolution.SetSize(480, 360);
     profile.max_resolution.SetSize(3840, 2160);
     // If we know MediaCodec will just create a software codec, prefer our
     // internal software decoder instead. It's more up to date and secured
@@ -1585,7 +1587,8 @@ AndroidVideoDecodeAccelerator::GetCapabilities(
 
   if (MediaCodecUtil::IsVp9DecoderAvailable()) {
     SupportedProfile profile;
-    profile.min_resolution.SetSize(0, 0);
+    // Limit to 360p, like we do for vp8.  See above.
+    profile.min_resolution.SetSize(480, 360);
     profile.max_resolution.SetSize(3840, 2160);
     // If we know MediaCodec will just create a software codec, prefer our
     // internal software decoder instead. It's more up to date and secured