Merge M50: "Cleanup MediaCodecUtil::GetDefaultCodecName()."

Merge M50: "Cleanup MediaCodecUtil::GetDefaultCodecName()."

There's no need to build an entire list of codecs and transport that
across JNI when we always want the first one in the list.

Notably this reduces the cost of GpuChildThread::OnInitialize() by
over 400ms on an N5 running Marshmallow (450.208ms vs 39.64ms)! The
reduction comes from VideoEncodeAccelerator no longer creating ~3
MediaCodec instances to determine the codec name during the call to
VideoEncodeAccelerator::GetSupportedProfiles() during child thread
startup. I suspect this will translate into real GPU process startup
improvements.

BUG=594814
TEST=codec lists match before after on KitKat below and above.

Review URL: https://codereview.chromium.org/1805163002

Cr-Commit-Position: refs/heads/master@{#381805}
(cherry picked from commit 5c1bee20afe6113087fc9a5781b5773a8894bbd4)

Committed: https://chromium.googlesource.com/chromium/src/+/5d1be6b220032081d607aeff1a97a686302dc284

[DaleCurtis, 2016-03-21 18:07:02]

Description was changed from

==========
Merge M50: "Cleanup MediaCodecUtil::GetDefaultCodecName()."

There's no need to build an entire list of codecs and transport that
across JNI when we always want the first one in the list.

Notably this reduces the cost of GpuChildThread::OnInitialize() by
over 400ms on an N5 running Marshmallow (450.208ms vs 39.64ms)! The
reduction comes from VideoEncodeAccelerator no longer creating ~3
MediaCodec instances to determine the codec name during the call to
VideoEncodeAccelerator::GetSupportedProfiles() during child thread
startup. I suspect this will translate into real GPU process startup
improvements.

BUG=594814
TEST=codec lists match before after on KitKat below and above.

Review URL: https://codereview.chromium.org/1805163002

Cr-Commit-Position: refs/heads/master@{#381805}
(cherry picked from commit 5c1bee20afe6113087fc9a5781b5773a8894bbd4)
==========

to

==========
Merge M50: "Cleanup MediaCodecUtil::GetDefaultCodecName()."

There's no need to build an entire list of codecs and transport that
across JNI when we always want the first one in the list.

Notably this reduces the cost of GpuChildThread::OnInitialize() by
over 400ms on an N5 running Marshmallow (450.208ms vs 39.64ms)! The
reduction comes from VideoEncodeAccelerator no longer creating ~3
MediaCodec instances to determine the codec name during the call to
VideoEncodeAccelerator::GetSupportedProfiles() during child thread
startup. I suspect this will translate into real GPU process startup
improvements.

BUG=594814
TEST=codec lists match before after on KitKat below and above.

Review URL: https://codereview.chromium.org/1805163002

Cr-Commit-Position: refs/heads/master@{#381805}
(cherry picked from commit 5c1bee20afe6113087fc9a5781b5773a8894bbd4)

Committed:
https://chromium.googlesource.com/chromium/src/+/5d1be6b220032081d607aeff1a97...
==========

[DaleCurtis, 2016-03-21 18:07:03]

Committed patchset #1 (id:1) manually as
5d1be6b220032081d607aeff1a97a686302dc284.