Enabling reading command line args in EG2 tests

Initialize base::CommandLine arguments from NSProcessInfo in EG2 test
bundle so that command line arguments can be accessed in EG2 test cases
through base::CommandLine::ForCurrentProcess().

Bug: 922813, 1000474
Change-Id: Ie214ca281fedd5f24b489e2f1605c28ce3abd669
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1833044Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Zhaoyang Li <zhaoyangli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702103}

ios/chrome/test/earl_grey/chrome_egtest_bundle_main.mm

@@ -10,6 +10,7 @@
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/logging.h"
+#include "base/strings/sys_string_conversions.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 #include "ui/base/resource/resource_bundle.h"
 
@@ -26,8 +27,27 @@ namespace {
 class TestMain {
  public:
   TestMain() {
-    // Initialize the CommandLine, because ResourceBundle requires it to exist.
-    base::CommandLine::Init(/*argc=*/0, /*argv=*/nullptr);
+    NSArray* arguments = NSProcessInfo.processInfo.arguments;
+
+    // Convert NSArray to the required input type of |base::CommandLine::Init|.
+    int argc = arguments.count;
+    const char* argv[argc];
+    std::vector<std::string> argv_store;
+    // Avoid using std::vector::push_back (or any other method that could cause
+    // the vector to grow) as this will cause the std::string to be copied or
+    // moved (depends on the C++ implementation) which may invalidates the
+    // pointer returned by std::string::c_str(). Even if the strings are moved,
+    // this may cause garbage if std::string uses optimisation for small strings
+    // (by returning pointer to the object internals in that case).
+    argv_store.resize(argc);
+    for (int i = 0; i < argc; i++) {
+      argv_store[i] = base::SysNSStringToUTF8(arguments[i]);
+      argv[i] = argv_store[i].c_str();
+    }
+
+    // Initialize the CommandLine with arguments. ResourceBundle requires
+    // CommandLine to exist.
+    base::CommandLine::Init(argc, argv);
 
     // Load pak files into the ResourceBundle.
     l10n_util::OverrideLocaleWithCocoaLocale();