Simplify mojo_shell since it's now only used for Mandoline.

mojo/shell/context.cc

Index: mojo/shell/context.cc
diff --git a/mojo/shell/context.cc b/mojo/shell/context.cc
index fbde07dd2ab0e6510a0905073a08a30e56ffae25..fc56476f819ea3392cb56a58ddb5b08aa9d4b71b 100644
--- a/mojo/shell/context.cc
+++ b/mojo/shell/context.cc
@@ -30,7 +30,6 @@
 #include "mojo/services/tracing/tracing.mojom.h"
 #include "mojo/shell/application_manager/application_loader.h"
 #include "mojo/shell/application_manager/application_manager.h"
-#include "mojo/shell/command_line_util.h"
 #include "mojo/shell/filename_util.h"
 #include "mojo/shell/in_process_native_runner.h"
 #include "mojo/shell/out_of_process_native_runner.h"
@@ -85,22 +84,6 @@ bool ConfigureURLMappings(const base::CommandLine& command_line,
     resolver->AddOriginMapping(GURL(origin_mapping.origin),
                                GURL(origin_mapping.base_url));
 
-  if (command_line.HasSwitch(switches::kURLMappings)) {
-    const std::string mappings =
-        command_line.GetSwitchValueASCII(switches::kURLMappings);
-
-    base::StringPairs pairs;
-    if (!base::SplitStringIntoKeyValuePairs(mappings, '=', ',', &pairs))
-      return false;
-    using StringPair = std::pair<std::string, std::string>;
-    for (const StringPair& pair : pairs) {
-      const GURL from(pair.first);
-      const GURL to = context->ResolveCommandLineURL(pair.second);
-      if (!from.is_valid() || !to.is_valid())
-        return false;
-      resolver->AddURLMapping(from, to);
-    }
-  }
   return true;
 }