Fix SplitRange() logic in SourceBufferRange to transfer next buffer position appropriately

Adds logic to transfer the waiting-for-next-keyframe state to the split range
if necessary.

BUG=NONE
TEST=media_unittests


Review URL: https://chromiumcodereview.appspot.com/10703125

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@146274 0039d316-1c4b-4281-b951-d872f2087c98

media/filters/source_buffer_stream.cc

@@ -825,12 +825,18 @@ SourceBufferRange* SourceBufferRange::SplitRange(base::TimeDelta timestamp) {
       new SourceBufferRange(
           removed_buffers, kNoTimestamp(), interbuffer_distance_cb_);
 
-  // If |next_buffer_index_| points to a buffer in |split_range|, update the
-  // |next_buffer_index_| of this range and |split_range| accordingly.
+  // If the next buffer position is now in |split_range|, update the state of
+  // this range and |split_range| accordingly.
   if (next_buffer_index_ >= static_cast<int>(buffers_.size())) {
+    DCHECK(!waiting_for_keyframe_);
     split_range->next_buffer_index_ = next_buffer_index_ - keyframe_index;
-    next_buffer_index_ = -1;
+    ResetNextBufferPosition();
+  } else if (waiting_for_keyframe_) {
+    split_range->waiting_for_keyframe_ = true;
+    split_range->next_keyframe_timestamp_ = next_keyframe_timestamp_;
+    ResetNextBufferPosition();
   }
+
   return split_range;
 }
 
@@ -885,7 +891,7 @@ bool SourceBufferRange::TruncateAt(
         BufferQueue saved(starting_point + next_buffer_offset, buffers_.end());
         removed_buffers->swap(saved);
       }
-      next_buffer_index_ = -1;
+      ResetNextBufferPosition();
       removed_next_buffer = true;
     }
   }

media/filters/source_buffer_stream_unittest.cc

@@ -893,6 +893,55 @@ TEST_F(SourceBufferStreamTest, End_Overlap_Selected_NoKeyframeAfterNew) {
   CheckExpectedBuffers(10, 10, &kDataB);
 }
 
+// This test covers the case where new buffers end-overlap an existing, selected
+// range, and there is no keyframe after the end of the new buffers, then the
+// range gets split.
+// index:  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0
+// old  :                     |A a a a a A*a*|
+// new  :            B b b b b B b b b b B
+// after:           |B b b b b B b b b b B|
+// new  :  A a a a a A
+// after: |A a a a a A|       |B b b b b B|
+// track:                                 |a|
+TEST_F(SourceBufferStreamTest, End_Overlap_Selected_NoKeyframeAfterNew2) {
+  // Append 7 buffers at positions 10 through 16.
+  NewSegmentAppend(10, 7, &kDataA);
+
+  // Seek to position 15, then move to position 16.
+  Seek(15);
+  CheckExpectedBuffers(15, 15, &kDataA);
+
+  // Now append 11 buffers at positions 5 through 15.
+  NewSegmentAppend(5, 11, &kDataB);
+  CheckExpectedRanges("{ [5,15) }");
+
+  // Now do another end-overlap to split the range into two parts, where the
+  // 2nd range should have the next buffer position.
+  NewSegmentAppend(0, 6, &kDataA);
+  CheckExpectedRanges("{ [0,5) [10,15) }");
+
+  // Check for data in the track buffer.
+  CheckExpectedBuffers(16, 16, &kDataA);
+
+  // Now there's no data to fulfill the request.
+  CheckNoNextBuffer();
+
+  // Add data to the 2nd range, should not be able to fulfill the next read
+  // until we've added a keyframe.
+  NewSegmentAppend(15, 1, &kDataB);
+  CheckNoNextBuffer();
+  for (int i = 16; i <= 19; i++) {
+    AppendBuffers(i, 1, &kDataB);
+    CheckNoNextBuffer();
+  }
+
+  // Now append a keyframe.
+  AppendBuffers(20, 1, &kDataB);
+
+  // We should be able to get the next buffer.
+  CheckExpectedBuffers(20, 20, &kDataB, true);
+}
+
 // This test covers the case when new buffers overlap the middle of a selected
 // range. This tests the case when there is no split and the next buffer is a
 // keyframe.