Revert unintended prevention of seeks on infinite duration media.

Preserves the looping behavior for 200-type sources, while reverting
the disabling of seeks for "non-streaming" type sources which report
an infinite duration. This reverts the unintended behavior change
from http://crrev.com/298565

BUG=412562,427412
TEST=live player works again. LayoutTest forthcoming.

Review URL: https://codereview.chromium.org/684473002

Cr-Commit-Position: refs/heads/master@{#301495}

content/renderer/media/android/webmediaplayer_android.cc

@@ -11,7 +11,6 @@
 #include "base/callback_helpers.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
-#include "base/float_util.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
 #include "base/single_thread_task_runner.h"
@@ -525,13 +524,13 @@ blink::WebTimeRanges WebMediaPlayerAndroid::buffered() const {
 }
 
 blink::WebTimeRanges WebMediaPlayerAndroid::seekable() const {
-  // 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.
-  blink::WebTimeRange seekable_range(0.0, seekable_end);
+  // TODO(dalecurtis): Technically this allows seeking on media which return an
+  // infinite duration.  While not expected, disabling this breaks semi-live
+  // players, http://crbug.com/427412.
+  const blink::WebTimeRange seekable_range(0.0, duration());
   return blink::WebTimeRanges(&seekable_range, 1);
 }
 

media/blink/webmediaplayer_impl.cc

@@ -495,15 +495,21 @@ blink::WebTimeRanges WebMediaPlayerImpl::buffered() const {
 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);
 }