[Blimp] Adds blimp engine browser test framework and LoadUrl test.

blimp/engine/app/blimp_engine_config.h

Index: blimp/engine/app/blimp_engine_config.h
diff --git a/blimp/engine/app/blimp_engine_config.h b/blimp/engine/app/blimp_engine_config.h
index b385c6fd10cabce9ce3ad0aa17cdcfd5901b5ed6..bba653b3e0460b0679c36441f396abc379fd6a76 100644
--- a/blimp/engine/app/blimp_engine_config.h
+++ b/blimp/engine/app/blimp_engine_config.h
@@ -17,6 +17,9 @@ class CommandLine;
 namespace blimp {
 namespace engine {
 
+// Set internal command line switches for Blimp engine.
+void SetCommandLineDefaults(base::CommandLine* command_line);
+
 // Class to hold all of the configuration bits necessary for the Blimp engine.
 //
 // The BlimpEngineConfig class is initialized from parameters provided on the