Revert unintended prevention of seeks on infinite duration media.

media/blink/webmediaplayer_impl.cc

 // 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/webmediaplayer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <string>
 #include <vector>
@@ skipping 477 matching lines @@
   if (duration != kInfiniteDuration()) {
     buffered_data_source_host_.AddBufferedTimeRanges(
         &buffered_time_ranges, duration);
   }
   return ConvertToWebTimeRanges(buffered_time_ranges);
 }
 
 blink::WebTimeRanges WebMediaPlayerImpl::seekable() const {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
-  // Media without duration are considered streaming and should not be seekable.
-  const double seekable_end = duration();
-  if (!base::IsFinite(seekable_end))
+  if (ready_state_ < WebMediaPlayer::ReadyStateHaveMetadata)
     return blink::WebTimeRanges();
 
-  // If we have a finite duration then use [0, duration] as the seekable range;
-  // unless it's a streaming source, in which case only allow a seek to zero.
-  blink::WebTimeRange seekable_range(
-      0.0, data_source_ && data_source_->IsStreaming() ? 0.0 : seekable_end);
+  const double seekable_end = duration();
+
+  // Allow a special exception for seeks to zero for streaming sources with a
+  // finite duration; this allows looping to work.
+  const bool allow_seek_to_zero = data_source_ && data_source_->IsStreaming() &&
+                                  base::IsFinite(seekable_end);
+
+  // TODO(dalecurtis): Technically this allows seeking on media which return an
+  // infinite duration so long as DataSource::IsStreaming() is false.  While not
+  // expected, disabling this breaks semi-live players, http://crbug.com/427412.
+  const blink::WebTimeRange seekable_range(
+      0.0, allow_seek_to_zero ? 0.0 : seekable_end);
   return blink::WebTimeRanges(&seekable_range, 1);
 }
 
 bool WebMediaPlayerImpl::didLoadingProgress() {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
   bool pipeline_progress = pipeline_.DidLoadingProgress();
   bool data_progress = buffered_data_source_host_.DidLoadingProgress();
   return pipeline_progress || data_progress;
 }
 
@@ skipping 509 matching lines @@
   compositor_task_runner_->PostTask(FROM_HERE,
                                     base::Bind(&GetCurrentFrameAndSignal,
                                                base::Unretained(compositor_),
                                                &video_frame,
                                                &event));
   event.Wait();
   return video_frame;
 }
 
 }  // namespace media