Merge remote-tracking branch 'origin/release-1.8.31.3-beta'

Pulling in upstream merge to local master.
diff --git a/README.md b/README.md
index 38b9864..63c8938 100644
--- a/README.md
+++ b/README.md
@@ -37,11 +37,11 @@
 
    ```bash
    $ cd ~
-   $ wget https://github.com/pagespeed/ngx_pagespeed/archive/v1.8.31.2-beta.zip
-   $ unzip v1.8.31.2-beta.zip # or unzip v1.8.31.2-beta
-   $ cd ngx_pagespeed-1.8.31.2-beta/
-   $ wget https://dl.google.com/dl/page-speed/psol/1.8.31.2.tar.gz
-   $ tar -xzvf 1.8.31.2.tar.gz # expands to psol/
+   $ wget https://github.com/pagespeed/ngx_pagespeed/archive/v1.8.31.3-beta.zip
+   $ unzip v1.8.31.3-beta.zip # or unzip v1.8.31.3-beta
+   $ cd ngx_pagespeed-1.8.31.3-beta/
+   $ wget https://dl.google.com/dl/page-speed/psol/1.8.31.3.tar.gz
+   $ tar -xzvf 1.8.31.3.tar.gz # expands to psol/
    ```
 
 3. Download and build nginx:
@@ -52,7 +52,7 @@
    $ wget http://nginx.org/download/nginx-1.6.0.tar.gz
    $ tar -xvzf nginx-1.6.0.tar.gz
    $ cd nginx-1.6.0/
-   $ ./configure --add-module=$HOME/ngx_pagespeed-1.8.31.2-beta
+   $ ./configure --add-module=$HOME/ngx_pagespeed-1.8.31.3-beta
    $ make
    $ sudo make install
    ```
@@ -91,7 +91,7 @@
 
 ```bash
 $ curl -I 'http://localhost:8050/some_page/' | grep X-Page-Speed
-X-Page-Speed: 1.8.31.2-...
+X-Page-Speed: 1.8.31.3-...
 ```
 
 Looking at the source of a few pages you should see various changes, such as
diff --git a/config b/config
index 34fda83..c5f454e 100644
--- a/config
+++ b/config
@@ -27,8 +27,8 @@
     echo "   You need to separately download the pagespeed library:"
     echo ""
     echo "     $ cd /path/to/ngx_pagespeed"
-    echo "     $ wget https://dl.google.com/dl/page-speed/psol/1.8.31.2.tar.gz"
-    echo "     $ tar -xzvf 1.8.31.2.tar.gz # expands to psol/"
+    echo "     $ wget https://dl.google.com/dl/page-speed/psol/1.8.31.3.tar.gz"
+    echo "     $ tar -xzvf 1.8.31.3.tar.gz # expands to psol/"
     echo ""
     echo "   Or see the installation instructions:"
     echo "     https://github.com/pagespeed/ngx_pagespeed#how-to-build"
diff --git a/test/nginx_system_test.sh b/test/nginx_system_test.sh
index 0f0dfe8..a3994be 100755
--- a/test/nginx_system_test.sh
+++ b/test/nginx_system_test.sh
@@ -2592,12 +2592,15 @@
 $WGET -o $OUTFILE -O /dev/null --header "If-None-Match: $ETAG" $URL
 check fgrep -q "awaiting response... 304" $OUTFILE
 
-start_test PageSpeed resources should have a content length.
+start_test PageSpeed CSS loaded in fallback mode is always chunked
+# This is because the domains in urls may be rewritten, changing content
+# length from what's in the cache.
 URL="$EXAMPLE_ROOT/styles/W.rewrite_css_images.css.pagespeed.cf.Hash.css"
-OUT=$($WGET_DUMP --save-headers $URL)
-check_from "$OUT" egrep -q $'^Content-Length: ([0-9])*\r$'
-check_not_from "$OUT" egrep -iq $'^Transfer-Encoding: chunked\r$'
-check_not_from "$OUT" egrep -iq $'^Connection: close\r$'
+fetch_until -save $URL "egrep -c Transfer-Encoding:" 1 "--save-headers"
+OUT=$(cat $FETCH_UNTIL_OUTFILE)
+check_from "$OUT" egrep -iq $'^Transfer-Encoding: chunked\r$'
+check_not_from "$OUT" egrep -iq '^Content-Length:'
+check_not_from "$OUT" egrep -iq '^Connection: close'
 
 start_test Downstream cache integration caching headers.
 URL="http://downstreamcacheresource.example.com/mod_pagespeed_example/images/"