diff --git a/ipc/chromium/src/base/message_loop.h b/ipc/chromium/src/base/message_loop.h
index 33016a3d1952..41c86ac54063 100644
--- a/ipc/chromium/src/base/message_loop.h
+++ b/ipc/chromium/src/base/message_loop.h
@@ -531,7 +531,6 @@ class MessageLoopForIO : public MessageLoop {
   typedef base::MessagePumpLibevent::Watcher Watcher;
   typedef base::MessagePumpLibevent::FileDescriptorWatcher
       FileDescriptorWatcher;
-  typedef base::LineWatcher LineWatcher;
 
   enum Mode {
     WATCH_READ = base::MessagePumpLibevent::WATCH_READ,
diff --git a/ipc/chromium/src/base/message_pump_libevent.cc b/ipc/chromium/src/base/message_pump_libevent.cc
index f7500fdfd9a3..c1f945bd4d48 100644
--- a/ipc/chromium/src/base/message_pump_libevent.cc
+++ b/ipc/chromium/src/base/message_pump_libevent.cc
@@ -16,7 +16,6 @@
 #include "base/logging.h"
 #include "base/scoped_nsautorelease_pool.h"
 #include "base/time.h"
-#include "nsDependentSubstring.h"
 #include "event.h"
 #include "mozilla/ProfilerLabels.h"
 #include "mozilla/ProfilerThreadSleep.h"
@@ -408,46 +407,4 @@ void MessagePumpLibevent::ScheduleDelayedWork(
   delayed_work_time_ = delayed_work_time;
 }
 
-void LineWatcher::OnFileCanReadWithoutBlocking(int aFd) {
-  ssize_t length = 0;
-
-  while (true) {
-    length = read(aFd, mReceiveBuffer.get(), mBufferSize - mReceivedIndex);
-    DCHECK(length <= ssize_t(mBufferSize - mReceivedIndex));
-    if (length <= 0) {
-      if (length < 0) {
-        if (errno == EINTR) {
-          continue;  // retry system call when interrupted
-        }
-        if (errno == EAGAIN || errno == EWOULDBLOCK) {
-          return;  // no data available: return and re-poll
-        }
-        DLOG(ERROR) << "Can't read from fd, error " << errno;
-      } else {
-        DLOG(ERROR) << "End of file";
-      }
-      // At this point, assume that we can't actually access
-      // the socket anymore, and indicate an error.
-      OnError();
-      mReceivedIndex = 0;
-      return;
-    }
-
-    while (length-- > 0) {
-      DCHECK(mReceivedIndex < mBufferSize);
-      if (mReceiveBuffer[mReceivedIndex] == mTerminator) {
-        nsDependentCSubstring message(mReceiveBuffer.get(), mReceivedIndex);
-        OnLineRead(aFd, message);
-        if (length > 0) {
-          DCHECK(mReceivedIndex < (mBufferSize - 1));
-          memmove(&mReceiveBuffer[0], &mReceiveBuffer[mReceivedIndex + 1],
-                  length);
-        }
-        mReceivedIndex = 0;
-      } else {
-        mReceivedIndex++;
-      }
-    }
-  }
-}
 }  // namespace base
diff --git a/ipc/chromium/src/base/message_pump_libevent.h b/ipc/chromium/src/base/message_pump_libevent.h
index ac2646806945..b1a7d474b3c8 100644
--- a/ipc/chromium/src/base/message_pump_libevent.h
+++ b/ipc/chromium/src/base/message_pump_libevent.h
@@ -9,8 +9,6 @@
 
 #include "base/message_pump.h"
 #include "base/time.h"
-#include "mozilla/UniquePtr.h"
-#include "nsStringFwd.h"
 
 // Declare structs we need from libevent.h rather than including it
 struct event_base;
@@ -178,36 +176,6 @@ class MessagePumpLibevent : public MessagePump {
   DISALLOW_COPY_AND_ASSIGN(MessagePumpLibevent);
 };
 
-/**
- *  LineWatcher overrides OnFileCanReadWithoutBlocking. It separates the read
- *  data by mTerminator and passes each line to OnLineRead.
- */
-class LineWatcher : public MessagePumpLibevent::Watcher {
- public:
-  LineWatcher(char aTerminator, int aBufferSize)
-      : mReceivedIndex(0), mBufferSize(aBufferSize), mTerminator(aTerminator) {
-    mReceiveBuffer = mozilla::MakeUnique<char[]>(mBufferSize);
-  }
-
-  ~LineWatcher() {}
-
- protected:
-  /**
-   * OnError will be called when |read| returns error. Derived class should
-   * implement this function to handle error cases when needed.
-   */
-  virtual void OnError() {}
-  virtual void OnLineRead(int aFd, nsDependentCSubstring& aMessage) = 0;
-  virtual void OnFileCanWriteWithoutBlocking(int /* aFd */) override {}
-
- private:
-  void OnFileCanReadWithoutBlocking(int aFd) final;
-
-  mozilla::UniquePtr<char[]> mReceiveBuffer;
-  int mReceivedIndex;
-  int mBufferSize;
-  char mTerminator;
-};
 }  // namespace base
 
 #endif  // BASE_MESSAGE_PUMP_LIBEVENT_H_