Revert of Clean up. Experimental user avatars removed. (https://codereview.chromium.org/395133002/)

Reason for revert:
This broke build:
http://build.chromium.org/p/chromium.webkit/builders/Linux%20ChromiumOS%20Tests%20%28dbg%29%282%29/builds/419

With error:
/mnt/data/b/build/slave/Linux_ChromiumOS_Tests__dbg__2_/build/src/out/Debug/app_shell_browsertests: symbol lookup error: /mnt/data/b/build/slave/Linux_ChromiumOS_Tests__dbg__2_/build/src/out/Debug/lib/libmedia.so: undefined symbol: Ebml_Serialize

Original issue's description:
> Clean up. Experimental user avatars removed.
> 
> BUG=387738
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284666

TBR=scherkus@chromium.org,nkostylev@chromium.org,merkulova@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=387738

Review URL: https://codereview.chromium.org/411523005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284676 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/chromeos/login/users/user.h

@@ -84,6 +84,11 @@ class User : public user_manager::UserInfo {
   const user_manager::UserImage::RawImage& raw_image() const {
     return user_image_.raw_image();
   }
+  bool has_animated_image() const { return user_image_.has_animated_image(); }
+  // Returns raw representation of animated user image.
+  const user_manager::UserImage::RawImage& animated_image() const {
+    return user_image_.animated_image();
+  }
 
   // Whether |raw_image| contains data in format that is considered safe to
   // decode in sensitive environment (on Login screen).

chrome/browser/resources/chromeos/user_images_grid.js

@@ -9,6 +9,18 @@ cr.define('options', function() {
   /** @const */ var GridSelectionController = cr.ui.GridSelectionController;
   /** @const */ var ListSingleSelectionModel = cr.ui.ListSingleSelectionModel;
 
+  /**
+   * Number of frames recorded by takeVideo().
+   * @const
+   */
+  var RECORD_FRAMES = 48;
+
+  /**
+   * FPS at which camera stream is recorded.
+   * @const
+   */
+  var RECORD_FPS = 16;
+
    /**
     * Dimensions for camera capture.
     * @const
@@ -478,6 +490,29 @@ cr.define('options', function() {
       return true;
     },
 
+    /**
+     * Performs video capture from the live camera stream.
+     * @param {function=} opt_callback Callback that receives taken video as
+     *     data URL of a vertically stacked PNG sprite.
+     */
+    takeVideo: function(opt_callback) {
+      var canvas = document.createElement('canvas');
+      canvas.width = CAPTURE_SIZE.width;
+      canvas.height = CAPTURE_SIZE.height * RECORD_FRAMES;
+      var ctx = canvas.getContext('2d');
+      // Force canvas initialization to prevent FPS lag on the first frame.
+      ctx.fillRect(0, 0, 1, 1);
+      var captureData = {
+        callback: opt_callback,
+        canvas: canvas,
+        ctx: ctx,
+        frameNo: 0,
+        lastTimestamp: new Date().getTime()
+      };
+      captureData.timer = window.setInterval(
+          this.captureVideoFrame_.bind(this, captureData), 1000 / RECORD_FPS);
+    },
+
     /**
      * Discard current photo and return to the live camera stream.
      */
@@ -534,6 +569,27 @@ cr.define('options', function() {
       return canvas.toDataURL('image/png');
     },
 
+    /**
+     * Capture next frame of the video being recorded after a takeVideo() call.
+     * @param {Object} data Property bag with the recorder details.
+     * @private
+     */
+    captureVideoFrame_: function(data) {
+      var lastTimestamp = new Date().getTime();
+      var delayMs = lastTimestamp - data.lastTimestamp;
+      console.error('Delay: ' + delayMs + ' (' + (1000 / delayMs + ' FPS)'));
+      data.lastTimestamp = lastTimestamp;
+
+      this.captureFrame_(this.cameraVideo_, data.ctx, CAPTURE_SIZE);
+      data.ctx.translate(0, CAPTURE_SIZE.height);
+
+      if (++data.frameNo == RECORD_FRAMES) {
+        window.clearTimeout(data.timer);
+        if (data.callback && typeof data.callback == 'function')
+          data.callback(data.canvas.toDataURL('image/png'));
+      }
+    },
+
     /**
      * Adds new image to the user image grid.
      * @param {string} src Image URL.

chrome/browser/ui/webui/options/chromeos/user_image_source.cc

@@ -19,15 +19,31 @@
 
 namespace {
 
+// Animated key is used in user image URL requests to specify that
+// animated version of user image is required. Without that key
+// non-animated version of user image should be returned.
+const char kKeyAnimated[] = "animated";
+
 // Parses the user image URL, which looks like
 // "chrome://userimage/user@host?key1=value1&...&key_n=value_n",
-// to user email.
+// to user email and optional parameters.
 void ParseRequest(const GURL& url,
-                  std::string* email) {
+                  std::string* email,
+                  bool* is_image_animated) {
   DCHECK(url.is_valid());
   *email = net::UnescapeURLComponent(url.path().substr(1),
                                     (net::UnescapeRule::URL_SPECIAL_CHARS |
                                      net::UnescapeRule::SPACES));
+  std::string url_spec = url.possibly_invalid_spec();
+  url::Component query = url.parsed_for_possibly_invalid_spec().query;
+  url::Component key, value;
+  *is_image_animated = false;
+  while (ExtractQueryKeyValue(url_spec.c_str(), &query, &key, &value)) {
+    if (url_spec.substr(key.begin, key.len) == kKeyAnimated) {
+      *is_image_animated = true;
+      break;
+    }
+  }
 }
 
 }  // namespace
@@ -37,10 +53,13 @@ namespace options {
 
 base::RefCountedMemory* UserImageSource::GetUserImage(
     const std::string& email,
+    bool is_image_animated,
     ui::ScaleFactor scale_factor) const {
   const chromeos::User* user = chromeos::UserManager::Get()->FindUser(email);
   if (user) {
-    if (user->has_raw_image()) {
+    if (user->has_animated_image() && is_image_animated) {
+      return new base::RefCountedBytes(user->animated_image());
+    } else if (user->has_raw_image()) {
       return new base::RefCountedBytes(user->raw_image());
     } else if (user->image_is_stub()) {
       return ResourceBundle::GetSharedInstance().
@@ -74,14 +93,26 @@ void UserImageSource::StartDataRequest(
     int render_frame_id,
     const content::URLDataSource::GotDataCallback& callback) {
   std::string email;
+  bool is_image_animated = false;
   GURL url(chrome::kChromeUIUserImageURL + path);
-  ParseRequest(url, &email);
-  callback.Run(GetUserImage(email, ui::SCALE_FACTOR_100P));
+  ParseRequest(url, &email, &is_image_animated);
+  callback.Run(GetUserImage(email, is_image_animated, ui::SCALE_FACTOR_100P));
 }
 
 std::string UserImageSource::GetMimeType(const std::string& path) const {
   // We need to explicitly return a mime type, otherwise if the user tries to
   // drag the image they get no extension.
+  std::string email;
+  bool is_image_animated = false;
+
+  GURL url(chrome::kChromeUIUserImageURL + path);
+  ParseRequest(url, &email, &is_image_animated);
+
+  if (is_image_animated) {
+    const chromeos::User* user = chromeos::UserManager::Get()->FindUser(email);
+    if (user && user->has_animated_image())
+      return "image/gif";
+  }
   return "image/png";
 }
 

chrome/browser/ui/webui/options/chromeos/user_image_source.h

@@ -35,9 +35,11 @@ class UserImageSource : public content::URLDataSource {
       const content::URLDataSource::GotDataCallback& callback) OVERRIDE;
   virtual std::string GetMimeType(const std::string& path) const OVERRIDE;
 
-  // Returns PNG encoded image for user with specified email. If there's
+  // Returns PNG or GIF (when possible and if |is_image_animated| flag
+  // is true) encoded image for user with specified email.  If there's
   // no user with such email, returns the first default image.
   base::RefCountedMemory* GetUserImage(const std::string& email,
+                                       bool is_image_animated,
                                        ui::ScaleFactor scale_factor) const;
 
  private:

components/user_manager/user_image/user_image.cc

@@ -15,6 +15,17 @@ namespace {
 // Default quality for encoding user images.
 const int kDefaultEncodingQuality = 90;
 
+bool IsAnimatedImage(const UserImage::RawImage& data) {
+  const char kGIFStamp[] = "GIF";
+  const size_t kGIFStampLength = sizeof(kGIFStamp) - 1;
+
+  if (data.size() >= kGIFStampLength &&
+      memcmp(&data[0], kGIFStamp, kGIFStampLength) == 0) {
+    return true;
+  }
+  return false;
+}
+
 bool EncodeImageSkia(const gfx::ImageSkia& image,
                      std::vector<unsigned char>* output) {
   TRACE_EVENT2("oobe", "EncodeImageSkia",
@@ -47,12 +58,14 @@ UserImage UserImage::CreateAndEncode(const gfx::ImageSkia& image) {
 
 UserImage::UserImage()
     : has_raw_image_(false),
+      has_animated_image_(false),
       is_safe_format_(false) {
 }
 
 UserImage::UserImage(const gfx::ImageSkia& image)
     : image_(image),
       has_raw_image_(false),
+      has_animated_image_(false),
       is_safe_format_(false) {
 }
 
@@ -60,9 +73,19 @@ UserImage::UserImage(const gfx::ImageSkia& image,
                      const RawImage& raw_image)
     : image_(image),
       has_raw_image_(false),
+      has_animated_image_(false),
       is_safe_format_(false) {
+  if (IsAnimatedImage(raw_image)) {
+    has_animated_image_ = true;
+    animated_image_ = raw_image;
+    if (EncodeImageSkia(image_, &raw_image_)) {
+      has_raw_image_ = true;
+      MarkAsSafe();
+    }
+  } else {
     has_raw_image_ = true;
     raw_image_ = raw_image;
+  }
 }
 
 UserImage::~UserImage() {}

components/user_manager/user_image/user_image.h

@@ -15,7 +15,8 @@
 namespace user_manager {
 
 // Wrapper class storing a still image and it's raw representation.  Could be
-// used for storing profile images and user wallpapers.
+// used for storing profile images (including animated profile images) and user
+// wallpapers.
 class USER_MANAGER_EXPORT UserImage {
  public:
   // TODO(ivankr): replace with RefCountedMemory to prevent copying.
@@ -33,6 +34,9 @@ class USER_MANAGER_EXPORT UserImage {
   explicit UserImage(const gfx::ImageSkia& image);
 
   // Creates a new instance from a given still frame and raw representation.
+  // |raw_image| can be animated, in which case animated_image() will return the
+  // original |raw_image| and raw_image() will return the encoded representation
+  // of |image|.
   UserImage(const gfx::ImageSkia& image, const RawImage& raw_image);
 
   virtual ~UserImage();
@@ -46,6 +50,10 @@ class USER_MANAGER_EXPORT UserImage {
   // Discards the stored raw image, freeing used memory.
   void DiscardRawImage();
 
+  // Optional raw representation of the animated image.
+  bool has_animated_image() const { return has_animated_image_; }
+  const RawImage& animated_image() const { return animated_image_; }
+
   // URL from which this image was originally downloaded, if any.
   void set_url(const GURL& url) { url_ = url; }
   GURL url() const { return url_; }
@@ -62,6 +70,8 @@ class USER_MANAGER_EXPORT UserImage {
   gfx::ImageSkia image_;
   bool has_raw_image_;
   RawImage raw_image_;
+  bool has_animated_image_;
+  RawImage animated_image_;
   GURL url_;
 
   // If image was loaded from the local file, file path is stored here.

media/BUILD.gn

@@ -450,6 +450,27 @@ component("media") {
     }
   }
 
+  if (is_chromeos) {
+    # A simple WebM encoder for animated avatars on ChromeOS.
+    sources += [
+      "formats/webm/chromeos/ebml_writer.cc",
+      "formats/webm/chromeos/ebml_writer.h",
+      "formats/webm/chromeos/webm_encoder.cc",
+      "formats/webm/chromeos/webm_encoder.h",
+    ]
+    deps += [
+      "//third_party/libvpx",
+      "//third_party/libyuv"
+    ]
+    # For VaapiVideoEncodeAccelerator.
+    if (cpu_arch != "arm" && use_x11) {
+      sources += [
+        "filters/h264_bitstream_buffer.cc",
+        "filters/h264_bitstream_buffer.h",
+      ]
+    }
+  }
+
   if (!is_ios) {
     deps += [ "//third_party/libyuv" ]
   }

media/formats/webm/chromeos/DEPS

+include_rules = [
+  "+libyuv",
+  "+third_party/libvpx",
+]

media/formats/webm/chromeos/ebml_writer.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/formats/webm/chromeos/ebml_writer.h"
+
+#include "media/base/media_export.h"
+
+extern "C" {
+#include "third_party/libvpx/source/libvpx/third_party/libmkv/EbmlWriter.h"
+
+EbmlGlobal::EbmlGlobal() {
+}
+
+EbmlGlobal::~EbmlGlobal() {
+}
+
+// These functions must be in the global namespace and visible to libmkv.
+
+void MEDIA_EXPORT Ebml_Write(EbmlGlobal* glob,
+                             const void* buffer,
+                             unsigned long len) {
+  glob->write_cb.Run(buffer, len);
+}
+
+void MEDIA_EXPORT Ebml_Serialize(EbmlGlobal* glob,
+                                 const void* buffer,
+                                 int buffer_size,
+                                 unsigned long len) {
+  glob->serialize_cb.Run(buffer, buffer_size, len);
+}
+
+}  // extern "C"

media/formats/webm/chromeos/ebml_writer.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_FORMATS_WEBM_CHROMEOS_EBML_WRITER_H_
+#define MEDIA_FORMATS_WEBM_CHROMEOS_EBML_WRITER_H_
+
+#include "base/callback.h"
+
+// This struct serves as a bridge betweeen static libmkv interface and Chrome's
+// base::Callback. Must be in the global namespace. See EbmlWriter.h.
+struct EbmlGlobal {
+  EbmlGlobal();
+  ~EbmlGlobal();
+
+  base::Callback<void(const void* buffer, unsigned long len)> write_cb;
+  base::Callback<void(const void* buffer, int buffer_size, unsigned long len)>
+      serialize_cb;
+};
+
+#endif  // MEDIA_FORMATS_WEBM_CHROMEOS_EBML_WRITER_H_

media/formats/webm/chromeos/webm_encoder.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/formats/webm/chromeos/webm_encoder.h"
+
+#include "base/bind.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
+#include "libyuv/convert.h"
+#include "libyuv/video_common.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+
+extern "C" {
+// Getting the right degree of C compatibility has been a constant struggle.
+// - Stroustrup, C++ Report, 12(7), July/August 2000.
+#define private priv
+#include "third_party/libvpx/source/libvpx/third_party/libmkv/EbmlIDs.h"
+#include "third_party/libvpx/source/libvpx/third_party/libmkv/EbmlWriter.h"
+#undef private
+}
+
+// Number of encoder threads to use.
+static const int kNumEncoderThreads = 2;
+
+// Need a fixed size serializer for the track ID. libmkv provides a 64 bit
+// one, but not a 32 bit one.
+static void Ebml_SerializeUnsigned32(EbmlGlobal* ebml,
+                                     unsigned long class_id,
+                                     uint64_t value) {
+  uint8 size_serialized = 4 | 0x80;
+  Ebml_WriteID(ebml, class_id);
+  Ebml_Serialize(ebml, &size_serialized, sizeof(size_serialized), 1);
+  Ebml_Serialize(ebml, &value, sizeof(value), 4);
+}
+
+// Wrapper functor for vpx_codec_destroy().
+struct VpxCodecDeleter {
+  void operator()(vpx_codec_ctx_t* codec) {
+    vpx_codec_destroy(codec);
+  }
+};
+
+// Wrapper functor for vpx_img_free().
+struct VpxImgDeleter {
+  void operator()(vpx_image_t* image) {
+    vpx_img_free(image);
+  }
+};
+
+namespace media {
+
+namespace chromeos {
+
+WebmEncoder::WebmEncoder(const base::FilePath& output_path,
+                         int bitrate,
+                         bool realtime)
+    : bitrate_(bitrate),
+      deadline_(realtime ? VPX_DL_REALTIME : VPX_DL_GOOD_QUALITY),
+      output_path_(output_path),
+      has_errors_(false) {
+  ebml_writer_.write_cb = base::Bind(
+      &WebmEncoder::EbmlWrite, base::Unretained(this));
+  ebml_writer_.serialize_cb = base::Bind(
+      &WebmEncoder::EbmlSerialize, base::Unretained(this));
+}
+
+WebmEncoder::~WebmEncoder() {
+}
+
+bool WebmEncoder::EncodeFromSprite(const SkBitmap& sprite,
+                                   int fps_n,
+                                   int fps_d) {
+  DCHECK(!sprite.isNull());
+  DCHECK(!sprite.empty());
+
+  has_errors_ = false;
+  width_ = sprite.width();
+  height_ = sprite.width();
+  fps_.num = fps_n;
+  fps_.den = fps_d;
+
+  // Sprite is tiled vertically.
+  frame_count_ = sprite.height() / width_;
+
+  vpx_image_t image;
+  vpx_img_alloc(&image, VPX_IMG_FMT_I420, width_, height_, 16);
+  // Ensure that image is freed after return.
+  scoped_ptr<vpx_image_t, VpxImgDeleter> image_ptr(&image);
+
+  const vpx_codec_iface_t* codec_iface = vpx_codec_vp8_cx();
+  DCHECK(codec_iface);
+  vpx_codec_err_t ret = vpx_codec_enc_config_default(codec_iface, &config_, 0);
+  DCHECK_EQ(VPX_CODEC_OK, ret);
+
+  config_.rc_target_bitrate = bitrate_;
+  config_.g_w = width_;
+  config_.g_h = height_;
+  config_.g_pass = VPX_RC_ONE_PASS;
+  config_.g_profile = 0;          // Default profile.
+  config_.g_threads = kNumEncoderThreads;
+  config_.rc_min_quantizer = 0;
+  config_.rc_max_quantizer = 63;  // Maximum possible range.
+  config_.g_timebase.num = fps_.den;
+  config_.g_timebase.den = fps_.num;
+  config_.kf_mode = VPX_KF_AUTO;  // Auto key frames.
+
+  vpx_codec_ctx_t codec;
+  ret = vpx_codec_enc_init(&codec, codec_iface, &config_, 0);
+  if (ret != VPX_CODEC_OK)
+    return false;
+  // Ensure that codec context is freed after return.
+  scoped_ptr<vpx_codec_ctx_t, VpxCodecDeleter> codec_ptr(&codec);
+
+  SkAutoLockPixels lock_sprite(sprite);
+
+  const uint8* src = reinterpret_cast<const uint8*>(sprite.getAddr32(0, 0));
+  size_t src_frame_size = sprite.getSize();
+  int crop_y = 0;
+
+  if (!WriteWebmHeader())
+    return false;
+
+  for (size_t frame = 0; frame < frame_count_ && !has_errors_; ++frame) {
+    int res = libyuv::ConvertToI420(
+        src, src_frame_size,
+        image.planes[VPX_PLANE_Y], image.stride[VPX_PLANE_Y],
+        image.planes[VPX_PLANE_U], image.stride[VPX_PLANE_U],
+        image.planes[VPX_PLANE_V], image.stride[VPX_PLANE_V],
+        0, crop_y,                // src origin
+        width_, sprite.height(),  // src size
+        width_, height_,          // dest size
+        libyuv::kRotate0,
+        libyuv::FOURCC_ARGB);
+    if (res) {
+      has_errors_ = true;
+      break;
+    }
+    crop_y += height_;
+
+    ret = vpx_codec_encode(&codec, &image, frame, 1, 0, deadline_);
+    if (ret != VPX_CODEC_OK) {
+      has_errors_ = true;
+      break;
+    }
+
+    vpx_codec_iter_t iter = NULL;
+    const vpx_codec_cx_pkt_t* packet;
+    while (!has_errors_ && (packet = vpx_codec_get_cx_data(&codec, &iter))) {
+      if (packet->kind == VPX_CODEC_CX_FRAME_PKT)
+        WriteWebmBlock(packet);
+    }
+  }
+
+  return WriteWebmFooter();
+}
+
+bool WebmEncoder::WriteWebmHeader() {
+  output_ = base::OpenFile(output_path_, "wb");
+  if (!output_)
+    return false;
+
+  // Global header.
+  StartSubElement(EBML);
+  {
+    Ebml_SerializeUnsigned(&ebml_writer_, EBMLVersion, 1);
+    Ebml_SerializeUnsigned(&ebml_writer_, EBMLReadVersion, 1);
+    Ebml_SerializeUnsigned(&ebml_writer_, EBMLMaxIDLength, 4);
+    Ebml_SerializeUnsigned(&ebml_writer_, EBMLMaxSizeLength, 8);
+    Ebml_SerializeString(&ebml_writer_, DocType, "webm");
+    Ebml_SerializeUnsigned(&ebml_writer_, DocTypeVersion, 2);
+    Ebml_SerializeUnsigned(&ebml_writer_, DocTypeReadVersion, 2);
+  }
+  EndSubElement();  // EBML
+
+  // Single segment with a video track.
+  StartSubElement(Segment);
+  {
+    StartSubElement(Info);
+    {
+      // All timecodes in the segment will be expressed in milliseconds.
+      Ebml_SerializeUnsigned(&ebml_writer_, TimecodeScale, 1000000);
+      double duration = 1000. * frame_count_ * fps_.den / fps_.num;
+      Ebml_SerializeFloat(&ebml_writer_, Segment_Duration, duration);
+    }
+    EndSubElement();  // Info
+
+    StartSubElement(Tracks);
+    {
+      StartSubElement(TrackEntry);
+      {
+        Ebml_SerializeUnsigned(&ebml_writer_, TrackNumber, 1);
+        Ebml_SerializeUnsigned32(&ebml_writer_, TrackUID, 1);
+        Ebml_SerializeUnsigned(&ebml_writer_, TrackType, 1);  // Video
+        Ebml_SerializeString(&ebml_writer_, CodecID, "V_VP8");
+
+        StartSubElement(Video);
+        {
+          Ebml_SerializeUnsigned(&ebml_writer_, PixelWidth, width_);
+          Ebml_SerializeUnsigned(&ebml_writer_, PixelHeight, height_);
+          Ebml_SerializeUnsigned(&ebml_writer_, StereoMode, 0);  // Mono
+          float fps = static_cast<float>(fps_.num) / fps_.den;
+          Ebml_SerializeFloat(&ebml_writer_, FrameRate, fps);
+        }
+        EndSubElement();  // Video
+      }
+      EndSubElement();  // TrackEntry
+    }
+    EndSubElement();  // Tracks
+
+    StartSubElement(Cluster); {
+      Ebml_SerializeUnsigned(&ebml_writer_, Timecode, 0);
+    }  // Cluster left open.
+  }  // Segment left open.
+
+  // No check for |has_errors_| here because |false| is only returned when
+  // opening file fails.
+  return true;
+}
+
+void WebmEncoder::WriteWebmBlock(const vpx_codec_cx_pkt_t* packet) {
+  bool is_keyframe = packet->data.frame.flags & VPX_FRAME_IS_KEY;
+  int64_t pts_ms = 1000 * packet->data.frame.pts * fps_.den / fps_.num;
+
+  DVLOG(1) << "Video packet @" << pts_ms << " ms "
+           << packet->data.frame.sz << " bytes "
+           << (is_keyframe ? "K" : "");
+
+  Ebml_WriteID(&ebml_writer_, SimpleBlock);
+
+  uint32 block_length = (packet->data.frame.sz + 4) | 0x10000000;
+  EbmlSerializeHelper(&block_length, 4);
+
+  uint8 track_number = 1 | 0x80;
+  EbmlSerializeHelper(&track_number, 1);
+
+  EbmlSerializeHelper(&pts_ms, 2);
+
+  uint8 flags = 0;
+  if (is_keyframe)
+    flags |= 0x80;
+  if (packet->data.frame.flags & VPX_FRAME_IS_INVISIBLE)
+    flags |= 0x08;
+  EbmlSerializeHelper(&flags, 1);
+
+  EbmlWrite(packet->data.frame.buf, packet->data.frame.sz);
+}
+
+bool WebmEncoder::WriteWebmFooter() {
+  EndSubElement();  // Cluster
+  EndSubElement();  // Segment
+  DCHECK(ebml_sub_elements_.empty());
+  return base::CloseFile(output_) && !has_errors_;
+}
+
+void WebmEncoder::StartSubElement(unsigned long class_id) {
+  Ebml_WriteID(&ebml_writer_, class_id);
+  ebml_sub_elements_.push(ftell(output_));
+  static const uint64_t kUnknownLen = 0x01FFFFFFFFFFFFFFLLU;
+  EbmlSerializeHelper(&kUnknownLen, 8);
+}
+
+void WebmEncoder::EndSubElement() {
+  DCHECK(!ebml_sub_elements_.empty());
+
+  long int end_pos = ftell(output_);
+  long int start_pos = ebml_sub_elements_.top();
+  ebml_sub_elements_.pop();
+
+  uint64_t size = (end_pos - start_pos - 8) | 0x0100000000000000ULL;
+  // Seek to the beginning of the sub-element and patch in the calculated size.
+  if (fseek(output_, start_pos, SEEK_SET)) {
+    has_errors_ = true;
+    LOG(ERROR) << "Error writing to " << output_path_.value();
+  }
+  EbmlSerializeHelper(&size, 8);
+
+  // Restore write position.
+  if (fseek(output_, end_pos, SEEK_SET)) {
+    has_errors_ = true;
+    LOG(ERROR) << "Error writing to " << output_path_.value();
+  }
+}
+
+void WebmEncoder::EbmlWrite(const void* buffer,
+                            unsigned long len) {
+  if (fwrite(buffer, 1, len, output_) != len) {
+    has_errors_ = true;
+    LOG(ERROR) << "Error writing to " << output_path_.value();
+  }
+}
+
+template <class T>
+void WebmEncoder::EbmlSerializeHelper(const T* buffer, unsigned long len) {
+  for (int i = len - 1; i >= 0; i--) {
+    uint8 c = *buffer >> (i * CHAR_BIT);
+    EbmlWrite(&c, 1);
+  }
+}
+
+void WebmEncoder::EbmlSerialize(const void* buffer,
+                                int buffer_size,
+                                unsigned long len) {
+  switch (buffer_size) {
+    case 1:
+      return EbmlSerializeHelper(static_cast<const int8_t*>(buffer), len);
+    case 2:
+      return EbmlSerializeHelper(static_cast<const int16_t*>(buffer), len);
+    case 4:
+      return EbmlSerializeHelper(static_cast<const int32_t*>(buffer), len);
+    case 8:
+      return EbmlSerializeHelper(static_cast<const int64_t*>(buffer), len);
+    default:
+      NOTREACHED() << "Invalid EbmlSerialize length: " << len;
+  }
+}
+
+}  // namespace chromeos
+
+}  // namespace media

media/formats/webm/chromeos/webm_encoder.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_FORMATS_WEBM_CHROMEOS_WEBM_ENCODER_H_
+#define MEDIA_FORMATS_WEBM_CHROMEOS_WEBM_ENCODER_H_
+
+#include <stdio.h>
+#include <stack>
+
+#include "base/files/file_path.h"
+#include "media/base/media_export.h"
+#include "media/formats/webm/chromeos/ebml_writer.h"
+
+extern "C" {
+#define VPX_CODEC_DISABLE_COMPAT 1
+#include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
+#include "third_party/libvpx/source/libvpx/vpx/vp8cx.h"
+}
+
+class SkBitmap;
+
+namespace base {
+class FilePath;
+}
+
+namespace media {
+
+namespace chromeos {
+
+// WebM encoder using libvpx. Currently only supports one-pass, constant bitrate
+// encoding of short files consisting of a single video track. Seek info and
+// cues are not supported, so generated .webm file does not strictly adhere to
+// WebM standard (http://www.webmproject.org/code/specs/container/).
+class MEDIA_EXPORT WebmEncoder {
+ public:
+  // Create new instance for writing to |output_path|. If |realtime| is |true|,
+  // uses realtime deadline, otherwise - "good quality" deadline.
+  WebmEncoder(const base::FilePath& output_path, int bitrate, bool realtime);
+  ~WebmEncoder();
+
+  // Encodes video from a Nx(N*M) sprite, having M frames of size NxN with FPS
+  // |fps_n/fps_d|. Must be called on a thread that allows disk IO.
+  // Returns |true| iff encoding and writing to file is successful.
+  bool EncodeFromSprite(const SkBitmap& sprite, int fps_n, int fps_d);
+
+ private:
+  // Writes global WebM header and starts a single video track. Returns |false|
+  // if there was an error opening file for writing.
+  bool WriteWebmHeader();
+
+  // Writes VPX packet to output file.
+  void WriteWebmBlock(const vpx_codec_cx_pkt_t* packet);
+
+  // Finishes video track and closes output file. Returns |false| if there were
+  // any error during encoding/writing file.
+  bool WriteWebmFooter();
+
+  // Starts a new WebM sub-element of given type. Those can be nested.
+  void StartSubElement(unsigned long class_id);
+
+  // Closes current top-level sub-element.
+  void EndSubElement();
+
+  // libmkv callbacks.
+  void EbmlWrite(const void* buffer, unsigned long len);
+  void EbmlSerialize(const void* buffer, int buffer_size, unsigned long len);
+
+  template <typename T>
+  void EbmlSerializeHelper(const T* buffer, unsigned long len);
+
+  // Video dimensions and FPS.
+  size_t width_;
+  size_t height_;
+  vpx_rational_t fps_;
+
+  // Number of frames in video.
+  size_t frame_count_;
+
+  // VPX config in use.
+  vpx_codec_enc_cfg_t config_;
+
+  // VPX parameters.
+  int bitrate_;
+  unsigned long deadline_;
+
+  // EbmlWriter context.
+  EbmlGlobal ebml_writer_;
+
+  // Stack with start offsets of currently open sub-elements.
+  std::stack<long int> ebml_sub_elements_;
+
+  base::FilePath output_path_;
+  FILE* output_;
+
+  // True if an error occured while encoding/writing to file.
+  bool has_errors_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebmEncoder);
+};
+
+}  // namespace chromeos
+
+}  // namespace media
+
+#endif  // MEDIA_FORMATS_WEBM_CHROMEOS_WEBM_ENCODER_H_

media/media.gyp

@@ -650,6 +650,19 @@
             'DISABLE_USER_INPUT_MONITOR',
           ],
         }],
+        # A simple WebM encoder for animated avatars on ChromeOS.
+        ['chromeos==1', {
+          'dependencies': [
+            '../third_party/libvpx/libvpx.gyp:libvpx',
+            '../third_party/libyuv/libyuv.gyp:libyuv',
+          ],
+          'sources': [
+            'formats/webm/chromeos/ebml_writer.cc',
+            'formats/webm/chromeos/ebml_writer.h',
+            'formats/webm/chromeos/webm_encoder.cc',
+            'formats/webm/chromeos/webm_encoder.h',
+          ],
+        }],
         # For VaapiVideoEncodeAccelerator.
         ['target_arch != "arm" and chromeos == 1 and use_x11 == 1', {
           'sources': [