Fix net::BrotliSourceStream to ignore trailing data.

net/filter/brotli_source_stream_unittest.cc

Index: net/filter/brotli_source_stream_unittest.cc
diff --git a/net/filter/brotli_source_stream_unittest.cc b/net/filter/brotli_source_stream_unittest.cc
index 4a0fd1e70f320f6c9b19a934a04de65b3336e327..eedb39ce9096e1f708dc89da2d7bd18c23ac19bb 100644
--- a/net/filter/brotli_source_stream_unittest.cc
+++ b/net/filter/brotli_source_stream_unittest.cc
@@ -98,6 +98,29 @@ TEST_F(BrotliSourceStreamTest, DecodeBrotliOneBlockSync) {
   EXPECT_EQ("BROTLI", brotli_stream()->Description());
 }
 
+// If there are data after decoding is done, ignore the data. crbug.com/659311.
+TEST_F(BrotliSourceStreamTest, IgnoreExtraData) {
+  std::string response_with_extra_data(encoded_buffer(), encoded_len());
+  size_t extra_length = 1000;
+  response_with_extra_data.append(extra_length, 'x');
+  source()->AddReadResult(response_with_extra_data.c_str(),
+                          encoded_len() + extra_length, OK,
+                          MockSourceStream::SYNC);
+  out_buffer_ = new IOBufferWithSize(kDefaultBufferSize);
+  std::string actual_output;
+  TestCompletionCallback callback;
+  while (true) {
+    int bytes_read = ReadStream(callback);
+    if (bytes_read == OK)
+      break;
+    ASSERT_GT(bytes_read, OK);
+    actual_output.append(out_data(), bytes_read);
+  }
+  EXPECT_EQ(source_data_len(), actual_output.size());
+  EXPECT_EQ(source_data(), actual_output);
+  EXPECT_EQ("BROTLI", brotli_stream()->Description());
+}
+
 // Basic scenario: decoding brotli data with big enough buffer.
 TEST_F(BrotliSourceStreamTest, DecodeBrotliTwoBlockSync) {
   source()->AddReadResult(encoded_buffer(), 10, OK, MockSourceStream::SYNC);