Fix MultibufferDataSource::GetSize

When file loading is finished ResourceMultiBufferDataProvider count
DataBuffer queue size twice, so GetSize returned incorrect value.

BUG=625515, 627525, 624853

patch from issue 2110853006 at patchset 1 (http://crrev.com/2110853006#ps1)

Review-Url: https://codereview.chromium.org/2133803004
Cr-Commit-Position: refs/heads/master@{#405242}

media/blink/multibuffer_data_source_unittest.cc

@@ -9,6 +9,7 @@
 #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"
@@ -1425,4 +1426,26 @@ 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

@@ -72,8 +72,11 @@ void ResourceMultiBufferDataProvider::Start() {
   request.setRequestContext(WebURLRequest::RequestContextVideo);
 
   DVLOG(1) << __FUNCTION__ << " @ " << byte_pos();
-  if (url_data_->length() > 0) {
-    DCHECK_LT(byte_pos(), url_data_->length()) << " " << url_data_->url();
+  if (url_data_->length() > 0 && byte_pos() >= url_data_->length()) {
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, base::Bind(&ResourceMultiBufferDataProvider::Terminate,
+                              weak_factory_.GetWeakPtr()));
+    return;
   }
 
   request.setHTTPHeaderField(
@@ -403,8 +406,6 @@ 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?
@@ -501,6 +502,11 @@ bool ResourceMultiBufferDataProvider::ParseContentRange(
   return true;
 }
 
+void ResourceMultiBufferDataProvider::Terminate() {
+  fifo_.push_back(DataBuffer::CreateEOSBuffer());
+  url_data_->multibuffer()->OnDataProviderEvent(this);
+}
+
 int64_t ResourceMultiBufferDataProvider::byte_pos() const {
   int64_t ret = pos_;
   ret += fifo_.size();

media/blink/resource_multibuffer_data_provider.h

@@ -75,6 +75,9 @@ class MEDIA_BLINK_EXPORT ResourceMultiBufferDataProvider
   friend class ResourceMultiBufferDataProviderTest;
   friend class MockBufferedDataSource;
 
+  // Callback used when we're asked to fetch data after the end of the file.
+  void Terminate();
+
   // Parse a Content-Range header into its component pieces and return true if
   // each of the expected elements was found & parsed correctly.
   // |*instance_size| may be set to kPositionNotSpecified if the range ends in