Delete now deprecated BufferedDataSource and friends.

media/blink/buffered_resource_loader.cc

Index: media/blink/buffered_resource_loader.cc
diff --git a/media/blink/buffered_resource_loader.cc b/media/blink/buffered_resource_loader.cc
deleted file mode 100644
index 09c9038126f37721aa05e586c8a69dec660bcbd0..0000000000000000000000000000000000000000
--- a/media/blink/buffered_resource_loader.cc
+++ /dev/null
@@ -1,834 +0,0 @@
-// Copyright 2013 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/blink/buffered_resource_loader.h"
-
-#include <stddef.h>
-#include <stdint.h>
-#include <limits>
-#include <utility>
-
-#include "base/bits.h"
-#include "base/callback_helpers.h"
-#include "base/metrics/histogram.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_util.h"
-#include "media/base/media_log.h"
-#include "media/blink/cache_util.h"
-#include "net/http/http_byte_range.h"
-#include "net/http/http_request_headers.h"
-#include "third_party/WebKit/public/platform/WebString.h"
-#include "third_party/WebKit/public/platform/WebURLError.h"
-#include "third_party/WebKit/public/platform/WebURLResponse.h"
-#include "third_party/WebKit/public/web/WebKit.h"
-#include "third_party/WebKit/public/web/WebURLLoaderOptions.h"
-
-using blink::WebFrame;
-using blink::WebString;
-using blink::WebURLError;
-using blink::WebURLLoader;
-using blink::WebURLLoaderOptions;
-using blink::WebURLRequest;
-using blink::WebURLResponse;
-
-namespace media {
-
-static const int kHttpOK = 200;
-static const int kHttpPartialContent = 206;
-
-// Define the number of bytes in a megabyte.
-static const int kMegabyte = 1024 * 1024;
-
-// Minimum capacity of the buffer in forward or backward direction.
-//
-// 2MB is an arbitrary limit; it just seems to be "good enough" in practice.
-static const int kMinBufferCapacity = 2 * kMegabyte;
-
-// Maximum capacity of the buffer in forward or backward direction. This is
-// effectively the largest single read the code path can handle.
-// 20MB is an arbitrary limit; it just seems to be "good enough" in practice.
-static const int kMaxBufferCapacity = 20 * kMegabyte;
-
-// Maximum number of bytes outside the buffer we will wait for in order to
-// fulfill a read. If a read starts more than 2MB away from the data we
-// currently have in the buffer, we will not wait for buffer to reach the read's
-// location and will instead reset the request.
-static const int kForwardWaitThreshold = 2 * kMegabyte;
-
-// Computes the suggested backward and forward capacity for the buffer
-// if one wants to play at |playback_rate| * the natural playback speed.
-// Use a value of 0 for |bitrate| if it is unknown.
-static void ComputeTargetBufferWindow(double playback_rate, int bitrate,
-                                      int* out_backward_capacity,
-                                      int* out_forward_capacity) {
-  static const int kDefaultBitrate = 200 * 1024 * 8;  // 200 Kbps.
-  static const int kMaxBitrate = 20 * kMegabyte * 8;  // 20 Mbps.
-  static const double kMaxPlaybackRate = 25.0;
-  static const int kTargetSecondsBufferedAhead = 10;
-  static const int kTargetSecondsBufferedBehind = 2;
-
-  // Use a default bit rate if unknown and clamp to prevent overflow.
-  if (bitrate <= 0)
-    bitrate = kDefaultBitrate;
-  bitrate = std::min(bitrate, kMaxBitrate);
-
-  // Only scale the buffer window for playback rates greater than 1.0 in
-  // magnitude and clamp to prevent overflow.
-  bool backward_playback = false;
-  if (playback_rate < 0.0) {
-    backward_playback = true;
-    playback_rate *= -1.0;
-  }
-
-  playback_rate = std::max(playback_rate, 1.0);
-  playback_rate = std::min(playback_rate, kMaxPlaybackRate);
-
-  int bytes_per_second = (bitrate / 8.0) * playback_rate;
-
-  // Clamp between kMinBufferCapacity and kMaxBufferCapacity.
-  *out_forward_capacity = std::max(
-      kTargetSecondsBufferedAhead * bytes_per_second, kMinBufferCapacity);
-  *out_backward_capacity = std::max(
-      kTargetSecondsBufferedBehind * bytes_per_second, kMinBufferCapacity);
-
-  *out_forward_capacity = std::min(*out_forward_capacity, kMaxBufferCapacity);
-  *out_backward_capacity = std::min(*out_backward_capacity, kMaxBufferCapacity);
-
-  if (backward_playback)
-    std::swap(*out_forward_capacity, *out_backward_capacity);
-}
-
-BufferedResourceLoader::BufferedResourceLoader(const GURL& url,
-                                               CORSMode cors_mode,
-                                               int64_t first_byte_position,
-                                               int64_t last_byte_position,
-                                               DeferStrategy strategy,
-                                               int bitrate,
-                                               double playback_rate,
-                                               MediaLog* media_log)
-    : buffer_(kMinBufferCapacity, kMinBufferCapacity),
-      loader_failed_(false),
-      defer_strategy_(strategy),
-      might_be_reused_from_cache_in_future_(true),
-      range_supported_(false),
-      saved_forward_capacity_(0),
-      url_(url),
-      cors_mode_(cors_mode),
-      first_byte_position_(first_byte_position),
-      last_byte_position_(last_byte_position),
-      single_origin_(true),
-      offset_(0),
-      content_length_(kPositionNotSpecified),
-      instance_size_(kPositionNotSpecified),
-      read_position_(0),
-      read_size_(0),
-      read_buffer_(NULL),
-      first_offset_(0),
-      last_offset_(0),
-      bitrate_(bitrate),
-      playback_rate_(playback_rate),
-      media_log_(media_log),
-      cancel_upon_deferral_(false) {
-  // Set the initial capacity of |buffer_| based on |bitrate_| and
-  // |playback_rate_|.
-  UpdateBufferWindow();
-}
-
-BufferedResourceLoader::~BufferedResourceLoader() {}
-
-void BufferedResourceLoader::Start(
-    const StartCB& start_cb,
-    const LoadingStateChangedCB& loading_cb,
-    const ProgressCB& progress_cb,
-    WebFrame* frame) {
-  // Make sure we have not started.
-  DCHECK(start_cb_.is_null());
-  DCHECK(loading_cb_.is_null());
-  DCHECK(progress_cb_.is_null());
-  DCHECK(!start_cb.is_null());
-  DCHECK(!loading_cb.is_null());
-  DCHECK(!progress_cb.is_null());
-  CHECK(frame);
-
-  start_cb_ = start_cb;
-  loading_cb_ = loading_cb;
-  progress_cb_ = progress_cb;
-
-  if (first_byte_position_ != kPositionNotSpecified) {
-    // TODO(hclam): server may not support range request so |offset_| may not
-    // equal to |first_byte_position_|.
-    offset_ = first_byte_position_;
-  }
-
-  // Prepare the request.
-  WebURLRequest request(url_);
-  // TODO(mkwst): Split this into video/audio.
-  request.setRequestContext(WebURLRequest::RequestContextVideo);
-
-  if (IsRangeRequest()) {
-    request.setHTTPHeaderField(
-        WebString::fromUTF8(net::HttpRequestHeaders::kRange),
-        WebString::fromUTF8(net::HttpByteRange::Bounded(
-            first_byte_position_, last_byte_position_).GetHeaderValue()));
-  }
-
-  frame->setReferrerForRequest(request, blink::WebURL());
-
-  // Disable compression, compression for audio/video doesn't make sense...
-  request.setHTTPHeaderField(
-      WebString::fromUTF8(net::HttpRequestHeaders::kAcceptEncoding),
-      WebString::fromUTF8("identity;q=1, *;q=0"));
-
-  // Check for our test WebURLLoader.
-  std::unique_ptr<WebURLLoader> loader;
-  if (test_loader_) {
-    loader = std::move(test_loader_);
-  } else {
-    WebURLLoaderOptions options;
-    if (cors_mode_ == kUnspecified) {
-      options.allowCredentials = true;
-      options.crossOriginRequestPolicy =
-          WebURLLoaderOptions::CrossOriginRequestPolicyAllow;
-    } else {
-      options.exposeAllResponseHeaders = true;
-      // The author header set is empty, no preflight should go ahead.
-      options.preflightPolicy = WebURLLoaderOptions::PreventPreflight;
-      options.crossOriginRequestPolicy =
-          WebURLLoaderOptions::CrossOriginRequestPolicyUseAccessControl;
-      if (cors_mode_ == kUseCredentials)
-        options.allowCredentials = true;
-    }
-    loader.reset(frame->createAssociatedURLLoader(options));
-  }
-
-  // Start the resource loading.
-  loader->loadAsynchronously(request, this);
-  active_loader_.reset(new ActiveLoader(std::move(loader)));
-  loading_cb_.Run(kLoading);
-}
-
-void BufferedResourceLoader::Stop() {
-  // Reset callbacks.
-  start_cb_.Reset();
-  loading_cb_.Reset();
-  progress_cb_.Reset();
-  read_cb_.Reset();
-
-  // Cancel and reset any active loaders.
-  active_loader_.reset();
-}
-
-void BufferedResourceLoader::Read(int64_t position,
-                                  int read_size,
-                                  uint8_t* buffer,
-                                  const ReadCB& read_cb) {
-  DCHECK(start_cb_.is_null());
-  DCHECK(read_cb_.is_null());
-  DCHECK(!read_cb.is_null());
-  DCHECK(buffer);
-  DCHECK_GT(read_size, 0);
-
-  // Save the parameter of reading.
-  read_cb_ = read_cb;
-  read_position_ = position;
-  read_size_ = read_size;
-  read_buffer_ = buffer;
-
-  // Reads should immediately fail if the loader also failed.
-  if (loader_failed_) {
-    DoneRead(kFailed, 0);
-    return;
-  }
-
-  // If we're attempting to read past the end of the file, return a zero
-  // indicating EOF.
-  //
-  // This can happen with callees that read in fixed-sized amounts for parsing
-  // or at the end of chunked 200 responses when we discover the actual length
-  // of the file.
-  if (instance_size_ != kPositionNotSpecified &&
-      instance_size_ <= read_position_) {
-    DVLOG(1) << "Appear to have seeked beyond EOS; returning 0.";
-    DoneRead(kOk, 0);
-    return;
-  }
-
-  // Make sure |offset_| and |read_position_| does not differ by a large
-  // amount.
-  if (read_position_ > offset_ + std::numeric_limits<int32_t>::max() ||
-      read_position_ < offset_ + std::numeric_limits<int32_t>::min()) {
-    DoneRead(kCacheMiss, 0);
-    return;
-  }
-
-  // Make sure |read_size_| is not too large for the buffer to ever be able to
-  // fulfill the read request.
-  if (read_size_ > kMaxBufferCapacity) {
-    DoneRead(kFailed, 0);
-    return;
-  }
-
-  // Prepare the parameters.
-  first_offset_ = read_position_ - offset_;
-  last_offset_ = first_offset_ + read_size_;
-
-  // If we can serve the request now, do the actual read.
-  if (CanFulfillRead()) {
-    ReadInternal();
-    UpdateDeferBehavior();
-    return;
-  }
-
-  // If we expect the read request to be fulfilled later, expand capacity as
-  // necessary and disable deferring.
-  if (WillFulfillRead()) {
-    // Advance offset as much as possible to create additional capacity.
-    int advance = std::min(first_offset_, buffer_.forward_bytes());
-    bool ret = buffer_.Seek(advance);
-    DCHECK(ret);
-
-    offset_ += advance;
-    first_offset_ -= advance;
-    last_offset_ -= advance;
-
-    // Expand capacity to accomodate a read that extends past the normal
-    // capacity.
-    //
-    // This can happen when reading in a large seek index or when the
-    // first byte of a read request falls within kForwardWaitThreshold.
-    if (last_offset_ > buffer_.forward_capacity()) {
-      saved_forward_capacity_ = buffer_.forward_capacity();
-      buffer_.set_forward_capacity(last_offset_);
-    }
-
-    // Make sure we stop deferring now that there's additional capacity.
-    DCHECK(!ShouldDefer())
-        << "Capacity was not adjusted properly to prevent deferring.";
-    UpdateDeferBehavior();
-
-    return;
-  }
-
-  // Make a callback to report failure.
-  DoneRead(kCacheMiss, 0);
-}
-
-int64_t BufferedResourceLoader::content_length() {
-  return content_length_;
-}
-
-int64_t BufferedResourceLoader::instance_size() {
-  return instance_size_;
-}
-
-bool BufferedResourceLoader::range_supported() {
-  return range_supported_;
-}
-
-/////////////////////////////////////////////////////////////////////////////
-// blink::WebURLLoaderClient implementation.
-void BufferedResourceLoader::willFollowRedirect(
-    WebURLLoader* loader,
-    WebURLRequest& newRequest,
-    const WebURLResponse& redirectResponse,
-    int64_t encodedDataLength) {
-  // The load may have been stopped and |start_cb| is destroyed.
-  // In this case we shouldn't do anything.
-  if (start_cb_.is_null()) {
-    // Set the url in the request to an invalid value (empty url).
-    newRequest.setURL(blink::WebURL());
-    return;
-  }
-
-  // Only allow |single_origin_| if we haven't seen a different origin yet.
-  if (single_origin_)
-    single_origin_ = url_.GetOrigin() == GURL(newRequest.url()).GetOrigin();
-
-  url_ = newRequest.url();
-}
-
-void BufferedResourceLoader::didSendData(
-    WebURLLoader* loader,
-    unsigned long long bytes_sent,
-    unsigned long long total_bytes_to_be_sent) {
-  NOTIMPLEMENTED();
-}
-
-void BufferedResourceLoader::didReceiveResponse(
-    WebURLLoader* loader,
-    const WebURLResponse& response) {
-  DVLOG(1) << "didReceiveResponse: HTTP/"
-           << (response.httpVersion() == WebURLResponse::HTTPVersion_0_9
-                   ? "0.9"
-                   : response.httpVersion() == WebURLResponse::HTTPVersion_1_0
-                         ? "1.0"
-                         : response.httpVersion() ==
-                                   WebURLResponse::HTTPVersion_1_1
-                               ? "1.1"
-                               : response.httpVersion() ==
-                                         WebURLResponse::HTTPVersion_2_0
-                                     ? "2.0"
-                                     : "Unknown")
-           << " " << response.httpStatusCode();
-  DCHECK(active_loader_.get());
-  response_original_url_ = response.wasFetchedViaServiceWorker()
-                               ? response.originalURLViaServiceWorker()
-                               : response.url();
-
-  // The loader may have been stopped and |start_cb| is destroyed.
-  // In this case we shouldn't do anything.
-  if (start_cb_.is_null())
-    return;
-
-  uint32_t reasons = GetReasonsForUncacheability(response);
-  might_be_reused_from_cache_in_future_ = reasons == 0;
-  UMA_HISTOGRAM_BOOLEAN("Media.CacheUseful", reasons == 0);
-  int shift = 0;
-  int max_enum = base::bits::Log2Ceiling(kMaxReason);
-  while (reasons) {
-    DCHECK_LT(shift, max_enum);  // Sanity check.
-    if (reasons & 0x1) {
-      UMA_HISTOGRAM_ENUMERATION("Media.UncacheableReason",
-                                shift,
-                                max_enum); // PRESUBMIT_IGNORE_UMA_MAX
-    }
-
-    reasons >>= 1;
-    ++shift;
-  }
-
-  // Expected content length can be |kPositionNotSpecified|, in that case
-  // |content_length_| is not specified and this is a streaming response.
-  content_length_ = response.expectedContentLength();
-
-  // We make a strong assumption that when we reach here we have either
-  // received a response from HTTP/HTTPS protocol or the request was
-  // successful (in particular range request). So we only verify the partial
-  // response for HTTP and HTTPS protocol.
-  if (url_.SchemeIsHTTPOrHTTPS()) {
-    bool partial_response = (response.httpStatusCode() == kHttpPartialContent);
-    bool ok_response = (response.httpStatusCode() == kHttpOK);
-
-    if (IsRangeRequest()) {
-      // Check to see whether the server supports byte ranges.
-      std::string accept_ranges =
-          response.httpHeaderField("Accept-Ranges").utf8();
-      range_supported_ = (accept_ranges.find("bytes") != std::string::npos);
-
-      // If we have verified the partial response and it is correct, we will
-      // return kOk. It's also possible for a server to support range requests
-      // without advertising "Accept-Ranges: bytes".
-      if (partial_response && VerifyPartialResponse(response)) {
-        range_supported_ = true;
-      } else if (ok_response && first_byte_position_ == 0 &&
-                 last_byte_position_ == kPositionNotSpecified) {
-        // We accept a 200 response for a Range:0- request, trusting the
-        // Accept-Ranges header, because Apache thinks that's a reasonable thing
-        // to return.
-        instance_size_ = content_length_;
-      } else {
-        MEDIA_LOG(ERROR, media_log_)
-            << "Failed loading buffered resource using range request due to "
-               "invalid server response. HTTP status code="
-            << response.httpStatusCode();
-        DoneStart(kFailed);
-        return;
-      }
-    } else {
-      instance_size_ = content_length_;
-      if (response.httpStatusCode() != kHttpOK) {
-        // We didn't request a range but server didn't reply with "200 OK".
-        MEDIA_LOG(ERROR, media_log_)
-            << "Failed loading buffered resource due to invalid server "
-               "response. HTTP status code=" << response.httpStatusCode();
-        DoneStart(kFailed);
-        return;
-      }
-    }
-
-  } else {
-    CHECK_EQ(instance_size_, kPositionNotSpecified);
-    if (content_length_ != kPositionNotSpecified) {
-      if (first_byte_position_ == kPositionNotSpecified)
-        instance_size_ = content_length_;
-      else if (last_byte_position_ == kPositionNotSpecified)
-        instance_size_ = content_length_ + first_byte_position_;
-    }
-  }
-
-  // Calls with a successful response.
-  DoneStart(kOk);
-}
-
-void BufferedResourceLoader::didReceiveData(WebURLLoader* loader,
-                                            const char* data,
-                                            int data_length,
-                                            int encoded_data_length,
-                                            int encoded_body_length) {
-  DVLOG(1) << "didReceiveData: " << data_length << " bytes";
-  DCHECK(active_loader_.get());
-  DCHECK_GT(data_length, 0);
-
-  buffer_.Append(reinterpret_cast<const uint8_t*>(data), data_length);
-
-  // If there is an active read request, try to fulfill the request.
-  if (HasPendingRead() && CanFulfillRead())
-    ReadInternal();
-
-  // At last see if the buffer is full and we need to defer the downloading.
-  UpdateDeferBehavior();
-
-  // Consume excess bytes from our in-memory buffer if necessary.
-  if (buffer_.forward_bytes() > buffer_.forward_capacity()) {
-    int excess = buffer_.forward_bytes() - buffer_.forward_capacity();
-    bool success = buffer_.Seek(excess);
-    DCHECK(success);
-    offset_ += first_offset_ + excess;
-  }
-
-  // Notify latest progress and buffered offset.
-  progress_cb_.Run(offset_ + buffer_.forward_bytes() - 1);
-  Log();
-}
-
-void BufferedResourceLoader::didDownloadData(
-    blink::WebURLLoader* loader,
-    int dataLength,
-    int encoded_data_length) {
-  NOTIMPLEMENTED();
-}
-
-void BufferedResourceLoader::didReceiveCachedMetadata(
-    WebURLLoader* loader,
-    const char* data,
-    int data_length) {
-  NOTIMPLEMENTED();
-}
-
-void BufferedResourceLoader::didFinishLoading(
-    WebURLLoader* loader,
-    double finishTime,
-    int64_t total_encoded_data_length) {
-  DVLOG(1) << "didFinishLoading";
-  DCHECK(active_loader_.get());
-
-  // We're done with the loader.
-  active_loader_.reset();
-  loading_cb_.Run(kLoadingFinished);
-
-  // If we didn't know the |instance_size_| we do now.
-  if (instance_size_ == kPositionNotSpecified) {
-    instance_size_ = offset_ + buffer_.forward_bytes();
-  }
-
-  // If there is a start callback, run it.
-  if (!start_cb_.is_null()) {
-    DCHECK(read_cb_.is_null())
-        << "Shouldn't have a read callback during start";
-    DoneStart(kOk);
-    return;
-  }
-
-  // Don't leave read callbacks hanging around.
-  if (HasPendingRead()) {
-    // Try to fulfill with what is in the buffer.
-    if (CanFulfillRead())
-      ReadInternal();
-    else
-      DoneRead(kCacheMiss, 0);
-  }
-}
-
-void BufferedResourceLoader::didFail(
-    WebURLLoader* loader,
-    const WebURLError& error) {
-  DVLOG(1) << "didFail: reason=" << error.reason
-           << ", isCancellation=" << error.isCancellation
-           << ", domain=" << error.domain.utf8().data()
-           << ", localizedDescription="
-           << error.localizedDescription.utf8().data();
-  DCHECK(active_loader_.get());
-  MEDIA_LOG(ERROR, media_log_)
-      << "Failed loading buffered resource. Error code=" << error.reason;
-
-  // We don't need to continue loading after failure.
-  //
-  // Keep it alive until we exit this method so that |error| remains valid.
-  std::unique_ptr<ActiveLoader> active_loader = std::move(active_loader_);
-  loader_failed_ = true;
-  loading_cb_.Run(kLoadingFailed);
-
-  // Don't leave start callbacks hanging around.
-  if (!start_cb_.is_null()) {
-    DCHECK(read_cb_.is_null())
-        << "Shouldn't have a read callback during start";
-    DoneStart(kFailed);
-    return;
-  }
-
-  // Don't leave read callbacks hanging around.
-  if (HasPendingRead()) {
-    DoneRead(kFailed, 0);
-  }
-}
-
-bool BufferedResourceLoader::HasSingleOrigin() const {
-  DCHECK(start_cb_.is_null())
-      << "Start() must complete before calling HasSingleOrigin()";
-  return single_origin_;
-}
-
-bool BufferedResourceLoader::DidPassCORSAccessCheck() const {
-  // Until Start() is done we don't know, assume no until we know.
-  if (!start_cb_.is_null())
-    return false;
-  return !loader_failed_ && cors_mode_ != kUnspecified;
-}
-
-void BufferedResourceLoader::UpdateDeferStrategy(DeferStrategy strategy) {
-  if (!might_be_reused_from_cache_in_future_ && strategy == kNeverDefer)
-    strategy = kCapacityDefer;
-  defer_strategy_ = strategy;
-  UpdateDeferBehavior();
-}
-
-void BufferedResourceLoader::SetPlaybackRate(double playback_rate) {
-  playback_rate_ = playback_rate;
-
-  // This is a pause so don't bother updating the buffer window as we'll likely
-  // get unpaused in the future.
-  if (playback_rate_ == 0.0)
-    return;
-
-  // Abort any cancellations in progress if playback starts.
-  if (playback_rate_ > 0 && cancel_upon_deferral_)
-    cancel_upon_deferral_ = false;
-
-  UpdateBufferWindow();
-}
-
-void BufferedResourceLoader::SetBitrate(int bitrate) {
-  DCHECK(bitrate >= 0);
-  bitrate_ = bitrate;
-  UpdateBufferWindow();
-}
-
-/////////////////////////////////////////////////////////////////////////////
-// Helper methods.
-
-void BufferedResourceLoader::UpdateBufferWindow() {
-  int backward_capacity;
-  int forward_capacity;
-  ComputeTargetBufferWindow(
-      playback_rate_, bitrate_, &backward_capacity, &forward_capacity);
-
-  // This does not evict data from the buffer if the new capacities are less
-  // than the current capacities; the new limits will be enforced after the
-  // existing excess buffered data is consumed.
-  buffer_.set_backward_capacity(backward_capacity);
-  buffer_.set_forward_capacity(forward_capacity);
-}
-
-void BufferedResourceLoader::UpdateDeferBehavior() {
-  if (!active_loader_)
-    return;
-
-  SetDeferred(ShouldDefer());
-}
-
-void BufferedResourceLoader::SetDeferred(bool deferred) {
-  if (active_loader_->deferred() == deferred)
-    return;
-
-  active_loader_->SetDeferred(deferred);
-  loading_cb_.Run(deferred ? kLoadingDeferred : kLoading);
-
-  if (deferred && cancel_upon_deferral_)
-    CancelUponDeferral();
-}
-
-bool BufferedResourceLoader::ShouldDefer() const {
-  switch(defer_strategy_) {
-    case kNeverDefer:
-      return false;
-
-    case kReadThenDefer:
-      DCHECK(read_cb_.is_null() || last_offset_ > buffer_.forward_bytes())
-          << "We shouldn't stop deferring if we can fulfill the read";
-      return read_cb_.is_null();
-
-    case kCapacityDefer:
-      return buffer_.forward_bytes() >= buffer_.forward_capacity();
-  }
-  NOTREACHED();
-  return false;
-}
-
-bool BufferedResourceLoader::CanFulfillRead() const {
-  // If we are reading too far in the backward direction.
-  if (first_offset_ < 0 && (first_offset_ + buffer_.backward_bytes()) < 0)
-    return false;
-
-  // If the start offset is too far ahead.
-  if (first_offset_ >= buffer_.forward_bytes())
-    return false;
-
-  // At the point, we verified that first byte requested is within the buffer.
-  // If the request has completed, then just returns with what we have now.
-  if (!active_loader_)
-    return true;
-
-  // If the resource request is still active, make sure the whole requested
-  // range is covered.
-  if (last_offset_ > buffer_.forward_bytes())
-    return false;
-
-  return true;
-}
-
-bool BufferedResourceLoader::WillFulfillRead() const {
-  // Trying to read too far behind.
-  if (first_offset_ < 0 && (first_offset_ + buffer_.backward_bytes()) < 0)
-    return false;
-
-  // Trying to read too far ahead.
-  if ((first_offset_ - buffer_.forward_bytes()) >= kForwardWaitThreshold)
-    return false;
-
-  // The resource request has completed, there's no way we can fulfill the
-  // read request.
-  if (!active_loader_)
-    return false;
-
-  return true;
-}
-
-void BufferedResourceLoader::ReadInternal() {
-  // Seek to the first byte requested.
-  bool ret = buffer_.Seek(first_offset_);
-  DCHECK(ret);
-
-  // Then do the read.
-  int read = buffer_.Read(read_buffer_, read_size_);
-  offset_ += first_offset_ + read;
-
-  // And report with what we have read.
-  DoneRead(kOk, read);
-}
-
-int64_t BufferedResourceLoader::first_byte_position() const {
-  return first_byte_position_;
-}
-
-// static
-bool BufferedResourceLoader::ParseContentRange(
-    const std::string& content_range_str,
-    int64_t* first_byte_position,
-    int64_t* last_byte_position,
-    int64_t* instance_size) {
-  const std::string kUpThroughBytesUnit = "bytes ";
-  if (!base::StartsWith(content_range_str, kUpThroughBytesUnit,
-                        base::CompareCase::SENSITIVE)) {
-    return false;
-  }
-  std::string range_spec =
-      content_range_str.substr(kUpThroughBytesUnit.length());
-  size_t dash_offset = range_spec.find("-");
-  size_t slash_offset = range_spec.find("/");
-
-  if (dash_offset == std::string::npos || slash_offset == std::string::npos ||
-      slash_offset < dash_offset || slash_offset + 1 == range_spec.length()) {
-    return false;
-  }
-  if (!base::StringToInt64(range_spec.substr(0, dash_offset),
-                           first_byte_position) ||
-      !base::StringToInt64(range_spec.substr(dash_offset + 1,
-                                             slash_offset - dash_offset - 1),
-                           last_byte_position)) {
-    return false;
-  }
-  if (slash_offset == range_spec.length() - 2 &&
-      range_spec[slash_offset + 1] == '*') {
-    *instance_size = kPositionNotSpecified;
-  } else {
-    if (!base::StringToInt64(range_spec.substr(slash_offset + 1),
-                             instance_size)) {
-      return false;
-    }
-  }
-  if (*last_byte_position < *first_byte_position ||
-      (*instance_size != kPositionNotSpecified &&
-       *last_byte_position >= *instance_size)) {
-    return false;
-  }
-
-  return true;
-}
-
-void BufferedResourceLoader::CancelUponDeferral() {
-  cancel_upon_deferral_ = true;
-  if (active_loader_ && active_loader_->deferred())
-    active_loader_.reset();
-}
-
-int64_t BufferedResourceLoader::GetMemoryUsage() const {
-  return buffer_.forward_bytes() + buffer_.backward_bytes();
-}
-
-bool BufferedResourceLoader::VerifyPartialResponse(
-    const WebURLResponse& response) {
-  int64_t first_byte_position, last_byte_position, instance_size;
-  if (!ParseContentRange(response.httpHeaderField("Content-Range").utf8(),
-                         &first_byte_position, &last_byte_position,
-                         &instance_size)) {
-    return false;
-  }
-
-  if (instance_size != kPositionNotSpecified) {
-    instance_size_ = instance_size;
-  }
-
-  if (first_byte_position_ != kPositionNotSpecified &&
-      first_byte_position_ != first_byte_position) {
-    return false;
-  }
-
-  // TODO(hclam): I should also check |last_byte_position|, but since
-  // we will never make such a request that it is ok to leave it unimplemented.
-  return true;
-}
-
-void BufferedResourceLoader::DoneRead(Status status, int bytes_read) {
-  if (saved_forward_capacity_) {
-    buffer_.set_forward_capacity(saved_forward_capacity_);
-    saved_forward_capacity_ = 0;
-  }
-  read_position_ = 0;
-  read_size_ = 0;
-  read_buffer_ = NULL;
-  first_offset_ = 0;
-  last_offset_ = 0;
-  Log();
-
-  base::ResetAndReturn(&read_cb_).Run(status, bytes_read);
-}
-
-
-void BufferedResourceLoader::DoneStart(Status status) {
-  base::ResetAndReturn(&start_cb_).Run(status);
-}
-
-bool BufferedResourceLoader::IsRangeRequest() const {
-  return first_byte_position_ != kPositionNotSpecified;
-}
-
-void BufferedResourceLoader::Log() {
-  media_log_->AddEvent(
-      media_log_->CreateBufferedExtentsChangedEvent(
-          offset_ - buffer_.backward_bytes(),
-          offset_,
-          offset_ + buffer_.forward_bytes()));
-}
-
-}  // namespace media