diff --git a/intl/strres/src/nsStringBundle.cpp b/intl/strres/src/nsStringBundle.cpp
index 5a7a50f7be7..53cb270fff1 100644
--- a/intl/strres/src/nsStringBundle.cpp
+++ b/intl/strres/src/nsStringBundle.cpp
@@ -24,6 +24,8 @@
 #include "nsIComponentManager.h"
 #include "nsIMemory.h"
 #include "nsIObserverService.h"
+#include "pratom.h"
+#include "prmem.h"
 #include "nsCOMArray.h"
 #include "nsTextFormatter.h"
 #include "nsIErrorService.h"
diff --git a/intl/uconv/src/nsConverterInputStream.cpp b/intl/uconv/src/nsConverterInputStream.cpp
index 578d8c167b3..3c0e3cc0054 100644
--- a/intl/uconv/src/nsConverterInputStream.cpp
+++ b/intl/uconv/src/nsConverterInputStream.cpp
@@ -7,7 +7,6 @@
 #include "nsIInputStream.h"
 #include "nsICharsetConverterManager.h"
 #include "nsIServiceManager.h"
-#include "nsReadLine.h"
 
 #define CONVERTER_BUFFER_SIZE 8192
 
@@ -54,7 +53,7 @@ NS_IMETHODIMP
 nsConverterInputStream::Close()
 {
     nsresult rv = mInput ? mInput->Close() : NS_OK;
-    mLineBuffer = nullptr;
+    PR_FREEIF(mLineBuffer);
     mInput = nullptr;
     mConverter = nullptr;
     mByteData = nullptr;
@@ -235,7 +234,8 @@ NS_IMETHODIMP
 nsConverterInputStream::ReadLine(nsAString& aLine, bool* aResult)
 {
   if (!mLineBuffer) {
-    mLineBuffer = new nsLineBuffer<PRUnichar>;
+    nsresult rv = NS_InitLineBuffer(&mLineBuffer);
+    if (NS_FAILED(rv)) return rv;
   }
-  return NS_ReadLine(this, mLineBuffer.get(), aLine, aResult);
+  return NS_ReadLine(this, mLineBuffer, aLine, aResult);
 }
diff --git a/intl/uconv/src/nsConverterInputStream.h b/intl/uconv/src/nsConverterInputStream.h
index 4e89f8d593a..f299ae2bfd3 100644
--- a/intl/uconv/src/nsConverterInputStream.h
+++ b/intl/uconv/src/nsConverterInputStream.h
@@ -7,15 +7,13 @@
 #include "nsIConverterInputStream.h"
 #include "nsIUnicharLineInputStream.h"
 #include "nsString.h"
+#include "nsReadLine.h"
 
-#include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "nsIUnicodeDecoder.h"
 #include "nsIByteBuffer.h"
 #include "nsIUnicharBuffer.h"
 
-template<typename T> class nsLineBuffer;
-
 #define NS_CONVERTERINPUTSTREAM_CONTRACTID "@mozilla.org/intl/converter-input-stream;1"
 
 // {2BC2AD62-AD5D-4b7b-A9DB-F74AE203C527}
@@ -60,5 +58,5 @@ class nsConverterInputStream : public nsIConverterInputStream,
     uint32_t  mUnicharDataLength;
     PRUnichar mReplacementChar;
 
-    nsAutoPtr<nsLineBuffer<PRUnichar> > mLineBuffer;
+    nsLineBuffer<PRUnichar>* mLineBuffer;    
 };
diff --git a/netwerk/base/public/nsReadLine.h b/netwerk/base/public/nsReadLine.h
index 1c42cc72a17..561017500b6 100644
--- a/netwerk/base/public/nsReadLine.h
+++ b/netwerk/base/public/nsReadLine.h
@@ -7,6 +7,7 @@
 #ifndef nsReadLine_h__
 #define nsReadLine_h__
 
+#include "prmem.h"
 #include "nsIInputStream.h"
 #include "mozilla/Likely.h"
 
@@ -41,13 +42,43 @@
 template<typename CharT>
 class nsLineBuffer {
   public:
-    nsLineBuffer() : start(buf), end(buf) { }
-
   CharT buf[kLineBufferSize+1];
   CharT* start;
   CharT* end;
 };
 
+/**
+ * Initialize a line buffer for use with NS_ReadLine.
+ *
+ * @param aBufferPtr
+ *        Pointer to pointer to a line buffer. Upon successful return,
+ *        *aBufferPtr will contain a valid pointer to a line buffer, for use
+ *        with NS_ReadLine. Use PR_Free when the buffer is no longer needed.
+ *
+ * @retval NS_OK Success.
+ * @retval NS_ERROR_OUT_OF_MEMORY Not enough memory to allocate the line buffer.
+ *
+ * @par Example:
+ * @code
+ *    nsLineBuffer* lb;
+ *    rv = NS_InitLineBuffer(&lb);
+ *    if (NS_SUCCEEDED(rv)) {
+ *      // do stuff...
+ *      PR_Free(lb);
+ *    }
+ * @endcode
+ */
+template<typename CharT>
+nsresult
+NS_InitLineBuffer (nsLineBuffer<CharT> ** aBufferPtr) {
+  *aBufferPtr = PR_NEW(nsLineBuffer<CharT>);
+  if (!(*aBufferPtr))
+    return NS_ERROR_OUT_OF_MEMORY;
+
+  (*aBufferPtr)->start = (*aBufferPtr)->end = (*aBufferPtr)->buf;
+  return NS_OK;
+}
+
 /**
  * Read a line from an input stream. Lines are separated by '\r' (0x0D) or '\n'
  * (0x0A), or "\r\n" or "\n\r".
@@ -55,7 +86,8 @@ class nsLineBuffer {
  * @param aStream
  *        The stream to read from
  * @param aBuffer
- *        The line buffer to use.  A single line buffer must not be used with
+ *        The line buffer to use. Must have been inited with
+ *        NS_InitLineBuffer before. A single line buffer must not be used with
  *        different input streams.
  * @param aLine [out]
  *        The string where the line will be stored.
diff --git a/netwerk/base/src/nsFileStreams.cpp b/netwerk/base/src/nsFileStreams.cpp
index 2420ffca400..cc7f7b1c5aa 100644
--- a/netwerk/base/src/nsFileStreams.cpp
+++ b/netwerk/base/src/nsFileStreams.cpp
@@ -418,7 +418,7 @@ nsFileInputStream::Close()
     }
 
     // null out mLineBuffer in case Close() is called again after failing
-    mLineBuffer = nullptr;
+    PR_FREEIF(mLineBuffer);
     nsresult rv = nsFileStreamBase::Close();
     if (NS_FAILED(rv)) return rv;
     if (mFile && (mBehaviorFlags & DELETE_ON_CLOSE)) {
@@ -453,9 +453,10 @@ nsFileInputStream::ReadLine(nsACString& aLine, bool* aResult)
     NS_ENSURE_SUCCESS(rv, rv);
 
     if (!mLineBuffer) {
-      mLineBuffer = new nsLineBuffer<char>;
+        nsresult rv = NS_InitLineBuffer(&mLineBuffer);
+        if (NS_FAILED(rv)) return rv;
     }
-    return NS_ReadLine(this, mLineBuffer.get(), aLine, aResult);
+    return NS_ReadLine(this, mLineBuffer, aLine, aResult);
 }
 
 NS_IMETHODIMP
@@ -464,7 +465,7 @@ nsFileInputStream::Seek(int32_t aWhence, int64_t aOffset)
     nsresult rv = DoPendingOpen();
     NS_ENSURE_SUCCESS(rv, rv);
 
-    mLineBuffer = nullptr;
+    PR_FREEIF(mLineBuffer); // this invalidates the line buffer
     if (!mFD) {
         if (mBehaviorFlags & REOPEN_ON_REWIND) {
             rv = Open(mFile, mIOFlags, mPerm);
diff --git a/netwerk/base/src/nsFileStreams.h b/netwerk/base/src/nsFileStreams.h
index 95d35fb1aef..112882dba5d 100644
--- a/netwerk/base/src/nsFileStreams.h
+++ b/netwerk/base/src/nsFileStreams.h
@@ -7,7 +7,6 @@
 #define nsFileStreams_h__
 
 #include "nsAlgorithm.h"
-#include "nsAutoPtr.h"
 #include "nsIFileStreams.h"
 #include "nsIFile.h"
 #include "nsIInputStream.h"
@@ -142,7 +141,7 @@ public:
     Create(nsISupports *aOuter, REFNSIID aIID, void **aResult);
 
 protected:
-    nsAutoPtr<nsLineBuffer<char> > mLineBuffer;
+    nsLineBuffer<char> *mLineBuffer;
 
     /**
      * The file being opened.
diff --git a/netwerk/base/src/nsSerializationHelper.cpp b/netwerk/base/src/nsSerializationHelper.cpp
index 146ee99188b..82ff90bf420 100644
--- a/netwerk/base/src/nsSerializationHelper.cpp
+++ b/netwerk/base/src/nsSerializationHelper.cpp
@@ -4,8 +4,9 @@
 
 #include "nsSerializationHelper.h"
 
+#include "plbase64.h"
+#include "prmem.h"
 
-#include "mozilla/Base64.h"
 #include "nsISerializable.h"
 #include "nsIObjectOutputStream.h"
 #include "nsIObjectInputStream.h"
@@ -15,8 +16,6 @@
 #include "nsComponentManagerUtils.h"
 #include "nsStringStream.h"
 
-using namespace mozilla;
-
 nsresult
 NS_SerializeToString(nsISerializable* obj, nsCSubstring& str)
 {
@@ -39,12 +38,30 @@ NS_SerializeToString(nsISerializable* obj, nsCSubstring& str)
 nsresult
 NS_DeserializeObject(const nsCSubstring& str, nsISupports** obj)
 {
-  nsCString decodedData;
-  nsresult rv = Base64Decode(str, decodedData);
-  NS_ENSURE_SUCCESS(rv, rv);
+  // Base64 maps 3 binary bytes -> 4 ASCII bytes.  If the original byte array
+  // does not have length 0 mod 3, the input is padded with zeros and the
+  // output is padded with a corresponding number of trailing '=' (which are
+  // then sometimes dropped).  To compute the correct length of the original
+  // byte array, we have to subtract the number of trailing '=' and then
+  // multiply by 3 and then divide by 4 (making sure this is an integer
+  // division).
 
+  uint32_t size = str.Length();
+  if (size > 0 && str[size-1] == '=') {
+    if (size > 1 && str[size-2] == '=') {
+      size -= 2;
+    } else {
+      size -= 1;
+    }
+  }
+  size = (size * 3) / 4;
+  char* buf = PL_Base64Decode(str.BeginReading(), str.Length(), nullptr);
+  if (!buf)
+    return NS_ERROR_OUT_OF_MEMORY;
   nsCOMPtr<nsIInputStream> stream;
-  rv = NS_NewCStringInputStream(getter_AddRefs(stream), decodedData);
+  nsresult rv = NS_NewCStringInputStream(getter_AddRefs(stream),
+                                         Substring(buf, size));
+  PR_Free(buf);
   NS_ENSURE_SUCCESS(rv, rv);
 
   nsCOMPtr<nsIObjectInputStream> objstream =
diff --git a/netwerk/base/src/nsSocketTransport2.cpp b/netwerk/base/src/nsSocketTransport2.cpp
index a348eb59b11..8e0b45efa7b 100644
--- a/netwerk/base/src/nsSocketTransport2.cpp
+++ b/netwerk/base/src/nsSocketTransport2.cpp
@@ -19,6 +19,7 @@
 #include "nsAutoPtr.h"
 #include "nsCOMPtr.h"
 #include "netCore.h"
+#include "prmem.h"
 #include "plstr.h"
 #include "prnetdb.h"
 #include "prerror.h"
diff --git a/netwerk/cache/nsCacheMetaData.cpp b/netwerk/cache/nsCacheMetaData.cpp
index d7dc37a32e7..929117e8473 100644
--- a/netwerk/cache/nsCacheMetaData.cpp
+++ b/netwerk/cache/nsCacheMetaData.cpp
@@ -6,6 +6,7 @@
 
 #include "nsCacheMetaData.h"
 #include "nsICacheEntryDescriptor.h"
+#include "prmem.h"
 
 const char *
 nsCacheMetaData::GetElement(const char * key)
@@ -151,7 +152,7 @@ nsresult
 nsCacheMetaData::EnsureBuffer(uint32_t bufSize)
 {
     if (mBufferSize < bufSize) {
-        char * buf = (char *)moz_realloc(mBuffer, bufSize);
+        char * buf = (char *)PR_REALLOC(mBuffer, bufSize);
         if (!buf) {
             return NS_ERROR_OUT_OF_MEMORY;
         }
diff --git a/netwerk/cache/nsCacheMetaData.h b/netwerk/cache/nsCacheMetaData.h
index e0879c1473f..6bd7b995d2e 100644
--- a/netwerk/cache/nsCacheMetaData.h
+++ b/netwerk/cache/nsCacheMetaData.h
@@ -18,8 +18,7 @@ public:
 
     ~nsCacheMetaData() {
         mBufferSize = mMetaSize = 0;  
-        moz_free(mBuffer);
-        mBuffer = nullptr;
+        PR_FREEIF(mBuffer);
     }
 
     const char *  GetElement(const char * key);
diff --git a/netwerk/protocol/data/nsDataChannel.cpp b/netwerk/protocol/data/nsDataChannel.cpp
index 9a68c7f27af..2699b787fe4 100644
--- a/netwerk/protocol/data/nsDataChannel.cpp
+++ b/netwerk/protocol/data/nsDataChannel.cpp
@@ -5,10 +5,8 @@
 
 // data implementation
 
-#include "nsDataChannel.h"
-
-#include "mozilla/Base64.h"
 #include "nsIOService.h"
+#include "nsDataChannel.h"
 #include "nsDataHandler.h"
 #include "nsNetUtil.h"
 #include "nsIPipe.h"
@@ -16,8 +14,9 @@
 #include "nsIOutputStream.h"
 #include "nsReadableUtils.h"
 #include "nsEscape.h"
-
-using namespace mozilla;
+#include "plbase64.h"
+#include "plstr.h"
+#include "prmem.h"
 
 nsresult
 nsDataChannel::OpenContentStream(bool async, nsIInputStream **result,
@@ -71,10 +70,17 @@ nsDataChannel::OpenContentStream(bool async, nsIInputStream **result,
         }
         resultLen = ((resultLen * 3) / 4);
 
-        nsAutoCString decodedData;
-        rv = Base64Decode(dataBuffer, decodedData);
-        NS_ENSURE_SUCCESS(rv, rv);
-        rv = bufOutStream->Write(decodedData.get(), resultLen, &contentLen);
+        // XXX PL_Base64Decode will return a null pointer for decoding
+        // errors.  Since those are more likely than out-of-memory,
+        // should we return NS_ERROR_MALFORMED_URI instead?
+        char * decodedData = PL_Base64Decode(dataBuffer.get(), dataLen, nullptr);
+        if (!decodedData) {
+            return NS_ERROR_OUT_OF_MEMORY;
+        }
+
+        rv = bufOutStream->Write(decodedData, resultLen, &contentLen);
+
+        PR_Free(decodedData);
     } else {
         rv = bufOutStream->Write(dataBuffer.get(), dataBuffer.Length(), &contentLen);
     }