Revert of Fix MultibufferDataSource::GetSize (patchset #1 id:1 of...

Revert of Fix MultibufferDataSource::GetSize (patchset #1 id:1 of https://codereview.chromium.org/2110853006/ )

Reason for revert:
I believe this CL is causing flakyness in the video related tests on the GPU FYI waterfall.

Examples:
https://build.chromium.org/p/chromium.gpu.fyi/builders/Win7%20Release%20%28NVIDIA%29/builds/25925
https://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20Release%20%28ATI%29/builds/48492
https://build.chromium.org/p/chromium.gpu.fyi/builders/Mac%20Retina%20Release/builds/5019

Seeing this in the output log:
[27562:1287:0630/083352:WARNING:webmediaplayer_impl.cc(335)] Using MultibufferDataSource
[27562:34423:0630/083352:ERROR:ffmpeg_demuxer.cc(1510)] OnReadFrameDone result=-541478725 IsMaxMemoryUsageReached=0
[27562:1287:0630/083352:WARNING:webmediaplayer_impl.cc(335)] Using MultibufferDataSource
[27562:1287:0630/083352:FATAL:resource_multibuffer_data_provider.cc(75)] Check failed: byte_pos() < url_data_->length() (32768 vs. 10292) http://127.0.0.1:53903/resources/red-green.theora.ogv

Original issue's description:
> Fix MultibufferDataSource::GetSize
>
> When file loading is finished ResourceMultiBufferDataProvider count
> DataBuffer queue size twice, so GetSize returned incorrect value.
>
> BUG=
>
> Committed: https://crrev.com/bbaba3c8053a39f6d11d78a6e4770b37a9639067
> Cr-Commit-Position: refs/heads/master@{#403123}

TBR=hubbe@chromium.org,kostya-k@yandex-team.ru
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=624853

Review-Url: https://codereview.chromium.org/2115483003
Cr-Commit-Position: refs/heads/master@{#403211}

media/blink/multibuffer_data_source_unittest.cc

@@ -9,7 +9,6 @@
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
-#include "base/strings/string_number_conversions.h"
 #include "media/base/media_log.h"
 #include "media/base/mock_filters.h"
 #include "media/base/test_helpers.h"
@@ -1426,26 +1425,4 @@ TEST_F(MultibufferDataSourceTest, LengthKnownAtEOF) {
   Stop();
 }
 
-TEST_F(MultibufferDataSourceTest, FileSizeLessThanBlockSize) {
-  Initialize(kHttpUrl, true);
-  GURL gurl(kHttpUrl);
-  blink::WebURLResponse response(gurl);
-  response.setHTTPStatusCode(200);
-  response.setHTTPHeaderField(
-      WebString::fromUTF8("Content-Length"),
-      WebString::fromUTF8(base::Int64ToString(kDataSize / 2)));
-  response.setExpectedContentLength(kDataSize / 2);
-  Respond(response);
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize / 2));
-  EXPECT_CALL(host_, SetTotalBytes(kDataSize / 2));
-  EXPECT_CALL(host_, AddBufferedByteRange(0, kDataSize * 2));
-  ReceiveData(kDataSize / 2);
-  FinishLoading();
-
-  int64_t len = 0;
-  EXPECT_TRUE(data_source_->GetSize(&len));
-  EXPECT_EQ(kDataSize / 2, len);
-  Stop();
-}
-
 }  // namespace media

media/blink/resource_multibuffer_data_provider.cc

@@ -402,6 +402,8 @@ void ResourceMultiBufferDataProvider::didFinishLoading(
 
   // If we didn't know the |instance_size_| we do now.
   int64_t size = byte_pos();
+  if (!fifo_.empty())
+    size += fifo_.back()->data_size();
 
   // This request reports something smaller than what we've seen in the past,
   // Maybe it's transient error?