Fix a bug that H264BitReader::ReadBits cannot read more than 16 bits.

TEST=H264BitReaderTest::ReadStreamWithoutEscapeAndTrailingZeroBytes in h264_parser_unittest.

Review URL: https://chromiumcodereview.appspot.com/10843057

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149733 0039d316-1c4b-4281-b951-d872f2087c98

content/common/gpu/media/h264_bit_reader.cc

@@ -66,7 +66,7 @@ bool H264BitReader::ReadBits(int num_bits, int *out) {
 
   while (num_remaining_bits_in_curr_byte_ < bits_left) {
     // Take all that's left in current byte, shift to make space for the rest.
-    *out = (curr_byte_ << (bits_left - num_remaining_bits_in_curr_byte_));
+    *out |= (curr_byte_ << (bits_left - num_remaining_bits_in_curr_byte_));
     bits_left -= num_remaining_bits_in_curr_byte_;
 
     if (!UpdateCurrByte())