[cros] Implement WebM encoder/muxer for animated avatar capture.

chrome/chrome_browser.gypi

Index: chrome/chrome_browser.gypi
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 9671de1098238736ba5b7f01db0fe783d9213b75..d472a203cf2eda08f0a193965d954de99c023b70 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -57,6 +57,8 @@
         '../third_party/libphonenumber/libphonenumber.gyp:libphonenumber',
         '../third_party/libusb/libusb.gyp:libusb',
         '../third_party/libxml/libxml.gyp:libxml',
+        '../third_party/libvpx/libvpx.gyp:libvpx',
+        '../third_party/libyuv/libyuv.gyp:libyuv',
         '../third_party/npapi/npapi.gyp:npapi',
         '../third_party/zlib/zlib.gyp:zlib',
         '../ui/base/strings/ui_strings.gyp:ui_strings',
@@ -502,6 +504,8 @@
         'browser/chromeos/device_settings_provider.h',
         'browser/chromeos/disks/disk_mount_manager.cc',
         'browser/chromeos/disks/disk_mount_manager.h',
+        'browser/chromeos/ebml_writer.cc',
+        'browser/chromeos/ebml_writer.h',
         'browser/chromeos/enrollment_dialog_view.cc',
         'browser/chromeos/enrollment_dialog_view.h',
         'browser/chromeos/enterprise_extension_observer.cc',
@@ -910,6 +914,8 @@
         'browser/chromeos/web_socket_proxy_controller.h',
         'browser/chromeos/web_socket_proxy_helper.cc',
         'browser/chromeos/web_socket_proxy_helper.h',
+        'browser/chromeos/webm_encoder.cc',
+        'browser/chromeos/webm_encoder.h',
         'browser/chromeos/xinput_hierarchy_changed_event_listener.cc',
         'browser/chromeos/xinput_hierarchy_changed_event_listener.h',
         'browser/chromeos/xinput_hierarchy_changed_event_listener_aura.cc',