Simple fallback implementation.

chrome/browser/net/spdyproxy/data_reduction_proxy_settings_android.cc

Index: chrome/browser/net/spdyproxy/data_reduction_proxy_settings_android.cc
diff --git a/chrome/browser/net/spdyproxy/data_reduction_proxy_settings_android.cc b/chrome/browser/net/spdyproxy/data_reduction_proxy_settings_android.cc
index 2c23fbff129edd09db973256d4673c68c5d3668a..e5ae091d2bc9c08177f0bbec76ab87520693b90f 100644
--- a/chrome/browser/net/spdyproxy/data_reduction_proxy_settings_android.cc
+++ b/chrome/browser/net/spdyproxy/data_reduction_proxy_settings_android.cc
@@ -55,6 +55,21 @@ enum {
   NUM_SPDY_PROXY_AUTH_STATE
 };
 
+// Generates a PAC proxy string component, including trailing semicolon and
+// space, for |origin|. Eg:
+//     "http://foo.com/"        -> "HTTP foo.com:80; "
+//     "https://bar.com:10443"  -> "HTTPS bar.coom:10443; "
+// The returned strings are suitable for concatenating into a PAC string.
+// If |origin| is empty, returns an empty string.
+std::string ProtocolAndHostForPACString(const std::string& origin) {
+  if (origin.empty()) {
+    return std::string();
+  }
+  GURL url = GURL(origin);
+  std::string protocol = url.SchemeIsSecure() ? "HTTPS "  : "HTTP ";
+  return protocol + net::HostPortPair::FromURL(url).ToString() + "; ";
+}
+
 }  // namespace
 
 DataReductionProxySettingsAndroid::DataReductionProxySettingsAndroid(
@@ -260,19 +275,18 @@ std::string DataReductionProxySettingsAndroid::GetProxyPacScript() {
       "(" + JoinString(pac_bypass_rules_, ") || (") + ")";
 
   // Generate a proxy PAC that falls back to direct loading when the proxy is
-  // unavailable and only process HTTP traffic. (With a statically configured
-  // proxy, proxy failures will simply result in a connection error presented to
-  // users.)
+  // unavailable and only process HTTP traffic.
 
-  std::string proxy_host =
-      DataReductionProxySettings::GetDataReductionProxyOriginHostPort();
+  std::string proxy_host = ProtocolAndHostForPACString(
+      DataReductionProxySettings::GetDataReductionProxyOrigin());
+  std::string fallback_host = ProtocolAndHostForPACString(
+      DataReductionProxySettings::GetDataReductionProxyFallback());
   std::string pac = "function FindProxyForURL(url, host) {"
       "  if (" + bypass_clause + ") {"
       "    return 'DIRECT';"
       "  } "
       "  if (url.substring(0, 5) == 'http:') {"
-      "    return 'HTTPS " + proxy_host +
-      "; DIRECT';"
+      "    return '" + proxy_host + fallback_host + "DIRECT';"
       "  }"
       "  return 'DIRECT';"
       "}";