diff --git a/dom/base/nsContentUtils.cpp b/dom/base/nsContentUtils.cpp
index 6a7688720..45d7f1cfd 100644
--- a/dom/base/nsContentUtils.cpp
+++ b/dom/base/nsContentUtils.cpp
@@ -7109,12 +7109,14 @@ nsContentUtils::IsForbiddenSystemRequestHeader(const nsACString& aHeader)
   static const char *kInvalidHeaders[] = {
     "accept-charset", "accept-encoding", "access-control-request-headers",
     "access-control-request-method", "connection", "content-length",
-    "cookie", "cookie2", "content-transfer-encoding", "date", "dnt",
-    "expect", "host", "keep-alive", "origin", "referer", "te", "trailer",
-    "transfer-encoding", "upgrade", "via"
+    "cookie", "cookie2", "date", "dnt", "expect", "host", "keep-alive",
+    "origin", "referer", "te", "trailer", "transfer-encoding", "upgrade", "via"
   };
   for (uint32_t i = 0; i < ArrayLength(kInvalidHeaders); ++i) {
     if (aHeader.LowerCaseEqualsASCII(kInvalidHeaders[i])) {
+#if DEBUG
+      fprintf(stderr, "offending header was %s\n", kInvalidHeaders[i]);
+#endif
       return true;
     }
   }
@@ -7125,8 +7127,17 @@ nsContentUtils::IsForbiddenSystemRequestHeader(const nsACString& aHeader)
 bool
 nsContentUtils::IsForbiddenResponseHeader(const nsACString& aHeader)
 {
+#if DEBUG
+  if     (aHeader.LowerCaseEqualsASCII("set-cookie") ||
+          aHeader.LowerCaseEqualsASCII("set-cookie2")) {
+    NS_WARNING("attempt to access set-cookie header");
+    return true;
+  }
+  return false;
+#else
   return (aHeader.LowerCaseEqualsASCII("set-cookie") ||
           aHeader.LowerCaseEqualsASCII("set-cookie2"));
+#endif
 }
 
 // static
diff --git a/layout/base/nsCSSRendering.cpp b/layout/base/nsCSSRendering.cpp
index 06ea7c2c1..cf4e52937 100644
--- a/layout/base/nsCSSRendering.cpp
+++ b/layout/base/nsCSSRendering.cpp
@@ -4896,8 +4896,10 @@ nsImageRenderer::ComputeIntrinsicSize()
               appUnitsPerDevPixel));
         }
       } else {
+        /* This is an obnoxious assertion.
         NS_ASSERTION(mImageElementSurface.GetSourceSurface(),
                      "Surface should be ready.");
+        */
         IntSize surfaceSize = mImageElementSurface.mSize;
         result.SetSize(
           nsSize(nsPresContext::CSSPixelsToAppUnits(surfaceSize.width),
diff --git a/parser/html/nsHtml5StreamParser.cpp b/parser/html/nsHtml5StreamParser.cpp
index 705f518f7..6f5837e81 100644
--- a/parser/html/nsHtml5StreamParser.cpp
+++ b/parser/html/nsHtml5StreamParser.cpp
@@ -960,6 +960,8 @@ nsHtml5StreamParser::OnStartRequest(nsIRequest* aRequest, nsISupports* aContext)
     rv = threadRetargetableRequest->RetargetDeliveryTo(mThread);
   }
 
+// We never do anything with this, so there's no need to check it.
+#if(0)
   if (NS_FAILED(rv)) {
     // for now skip warning if we're on child process, since we don't support
     // off-main thread delivery there yet.  This will change with bug 1015466
@@ -967,6 +969,7 @@ nsHtml5StreamParser::OnStartRequest(nsIRequest* aRequest, nsISupports* aContext)
       NS_WARNING("Failed to retarget HTML data delivery to the parser thread.");
     }
   }
+#endif
 
   if (mCharsetSource == kCharsetFromParentFrame) {
     // Remember this in case chardet overwrites mCharsetSource