Update mojo shell so that --args-for can be used on android

This refactor the shell startup to factorize the parsing of --args-for argument
so that it can be reused on android.

It also changes the way android gets its application argument. Instead of
expecting it as a specific intent parameter, it does exactly as the desktop
version and looks for it in the generic argument list.

R=sky@chromium.org

Review URL: https://codereview.chromium.org/816473002
diff --git a/shell/command_line_util.cc b/shell/command_line_util.cc
new file mode 100644
index 0000000..d8d693f
--- /dev/null
+++ b/shell/command_line_util.cc
@@ -0,0 +1,89 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "shell/command_line_util.h"
+
+#include <functional>
+
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/strings/string_split.h"
+#include "base/strings/utf_string_conversions.h"
+#include "shell/context.h"
+#include "shell/switches.h"
+
+namespace mojo {
+namespace shell {
+
+namespace {
+GURL GetAppURLAndSetArgs(const std::string& app_url_and_args,
+                         Context* context) {
+  std::vector<std::string> args;
+  GURL app_url = GetAppURLAndArgs(app_url_and_args, &args);
+
+  if (args.size() > 1)
+    context->application_manager()->SetArgsForURL(args, app_url);
+  return app_url;
+}
+}  // namespace
+
+bool ParseArgsFor(const std::string& arg, std::string* value) {
+  const std::string kArgsForSwitches[] = {
+      "-" + std::string(switches::kArgsFor) + "=",
+      "--" + std::string(switches::kArgsFor) + "=",
+  };
+  for (size_t i = 0; i < arraysize(kArgsForSwitches); i++) {
+    const std::string& argsfor_switch = kArgsForSwitches[i];
+    if (arg.compare(0, argsfor_switch.size(), argsfor_switch) == 0) {
+      *value = arg.substr(argsfor_switch.size(), std::string::npos);
+      return true;
+    }
+  }
+  return false;
+}
+
+GURL GetAppURLAndArgs(const std::string& app_url_and_args,
+                      std::vector<std::string>* args) {
+  // SplitString() returns empty strings for extra delimeter characters (' ').
+  base::SplitString(app_url_and_args, ' ', args);
+  args->erase(std::remove_if(args->begin(), args->end(),
+                             std::mem_fun_ref(&std::string::empty)),
+              args->end());
+
+  if (args->empty())
+    return GURL();
+  GURL app_url((*args)[0]);
+  if (!app_url.is_valid()) {
+    LOG(ERROR) << "Error: invalid URL: " << (*args)[0];
+    return app_url;
+  }
+  if (args->size() == 1)
+    args->clear();
+  return app_url;
+}
+
+void ApplyApplicationArgs(Context* context, const std::string& args) {
+  std::string args_for_value;
+  if (ParseArgsFor(args, &args_for_value))
+    GetAppURLAndSetArgs(args_for_value, context);
+}
+
+void RunCommandLineApps(Context* context) {
+  const auto& command_line = *base::CommandLine::ForCurrentProcess();
+  for (const auto& arg : command_line.GetArgs()) {
+    std::string arg2;
+#if defined(OS_WIN)
+    arg2 = base::UTF16ToUTF8(arg);
+#else
+    arg2 = arg;
+#endif
+    GURL url = GetAppURLAndSetArgs(arg2, context);
+    if (!url.is_valid())
+      return;
+    context->Run(url);
+  }
+}
+
+}  // namespace shell
+}  // namespace mojo