Make ChunkDemuxer::SetTimestampOffset take a TimeDelta instead of double

media/filters/chunk_demuxer_unittest.cc

Index: media/filters/chunk_demuxer_unittest.cc
diff --git a/media/filters/chunk_demuxer_unittest.cc b/media/filters/chunk_demuxer_unittest.cc
index d266a8ae12da915c0d534297e19d1b93b56554ae..1cdd51f6a36c40224f0fbe6ba15e14075342ebb3 100644
--- a/media/filters/chunk_demuxer_unittest.cc
+++ b/media/filters/chunk_demuxer_unittest.cc
@@ -77,6 +77,18 @@ MATCHER(IsEndOfStream, "") {
   return arg && arg->IsEndOfStream();
 }
 
+// Note: This matcher is needed because of a precision error in 32-bit linux.
+// If 32-bit linux is compiled with -march=pentium4 -msse2 -mfpmath=sse, the
+// precision error goes away. These flags are turned on in Chromium but off in
+// Chrome so that people with older CPUs can run Chrome.
+MATCHER_P(ApproximatelyEquals, timestamp, "") {
+  base::TimeDelta delta = base::TimeDelta::FromMicroseconds(
+      std::abs(timestamp.InMicroseconds() - arg.InMicroseconds()));
+
+  // 5 microseconds is chosen arbitrarily.
+  return delta < base::TimeDelta::FromMicroseconds(5);
+}
+
 static void OnReadDone(const base::TimeDelta& expected_time,
                        bool* called,
                        DemuxerStream::Status status,
@@ -2320,9 +2332,10 @@ TEST_F(ChunkDemuxerTest, TestDurationChangeTimestampOffset) {
                                            kDefaultDuration().InSecondsF()));

[Ami GONE FROM CHROMIUM, 2012/08/14 00:05:18]

Per offline convo: IWBN if ChunkDemuxer dealt only in TimeDeltas, and WMPI hid
the |double seconds| specified in the Media Source API.  As a side-effect, this
test would stop dividing, and hopefully be independent of the vagaries of 80-bit
register math on x86.

   scoped_ptr<Cluster> cluster = GenerateCluster(0, 4);
 
-  EXPECT_CALL(host_, SetDuration(
-      kDefaultDuration() + base::TimeDelta::FromMilliseconds(
-          kAudioBlockDuration * 2)));
+  base::TimeDelta expected_duration = kDefaultDuration() +
+      base::TimeDelta::FromMilliseconds(kAudioBlockDuration * 2);
+
+  EXPECT_CALL(host_, SetDuration(ApproximatelyEquals(expected_duration)));
   ASSERT_TRUE(AppendData(cluster->data(), cluster->size()));
 }