Add Mojo application test support to Chromium.

Needed to support Chromium Mojo application tests:
For example: https://codereview.chromium.org/709923003
The Mojo CL: https://codereview.chromium.org/695593002
(env changes support the cross-repo ApplicationTestBase)

TODO: Add GYP versions of GN apptest support targets.

BUG=392646
TEST=mojo/application:test_support builds with GN.
R=jamesr@chromium.org

Review URL: https://codereview.chromium.org/710403002

Cr-Commit-Position: refs/heads/master@{#303779}

mojo/application/BUILD.gn

@@ -18,3 +18,11 @@ source_set("application") {
     "//mojo/environment:chromium",
   ]
 }
+
+source_set("test_support") {
+  testonly = true
+  sources = [ "application_test_main_chromium.cc" ]
+
+  public_deps = [ "//mojo/public/cpp/application:test_support" ]
+  deps = [ "//base" ]
+}

mojo/application/application_test_main_chromium.cc

@@ -0,0 +1,51 @@
+// 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 "base/at_exit.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "mojo/public/c/system/main.h"
+#include "mojo/public/cpp/application/application_delegate.h"
+#include "mojo/public/cpp/application/application_impl.h"
+#include "mojo/public/cpp/application/application_test_base.h"
+#include "mojo/public/cpp/system/message_pipe.h"
+
+MojoResult MojoMain(MojoHandle shell_handle) {
+  // An AtExitManager instance is needed to construct message loops.
+  base::AtExitManager at_exit;
+
+  {
+    // This loop is used for init, and then destroyed before running tests.
+    base::MessageLoop message_loop;
+
+    // Construct an ApplicationImpl just for the GTEST commandline arguments.
+    // GTEST command line arguments are supported amid application arguments:
+    // $ mojo_shell 'mojo:example_apptests arg1 --gtest_filter=foo arg2'
+    mojo::ApplicationDelegate dummy_application_delegate;
+    mojo::ApplicationImpl app(&dummy_application_delegate, shell_handle);
+    CHECK(app.WaitForInitialize());
+
+    // InitGoogleTest expects (argc + 1) elements, including a terminating NULL.
+    // It also removes GTEST arguments from |argv| and updates the |argc| count.
+    // TODO(msw): Provide tests access to these actual command line arguments.
+    const std::vector<std::string>& args = app.args();
+    CHECK_LT(args.size(), static_cast<size_t>(std::numeric_limits<int>::max()));
+    int argc = static_cast<int>(args.size());
+    std::vector<const char*> argv(argc + 1);
+    for (int i = 0; i < argc; ++i)
+      argv[i] = args[i].c_str();
+    argv[argc] = nullptr;
+
+    testing::InitGoogleTest(&argc, const_cast<char**>(&(argv[0])));
+    mojo::test::SetShellHandle(app.UnbindShell());
+  }
+
+  int result = RUN_ALL_TESTS();
+
+  shell_handle = mojo::test::PassShellHandle().release().value();
+  MojoResult close_result = MojoClose(shell_handle);
+  CHECK_EQ(close_result, MOJO_RESULT_OK);
+
+  return (result == 0) ? MOJO_RESULT_OK : MOJO_RESULT_UNKNOWN;
+}

mojo/environment/BUILD.gn

@@ -28,6 +28,8 @@ component("chromium_impl") {
     "default_async_waiter_impl.h",
     "default_logger_impl.cc",
     "default_logger_impl.h",
+    "default_run_loop_impl.cc",
+    "default_run_loop_impl.h",
   ]
 
   defines = [

mojo/environment/default_run_loop_impl.cc

@@ -0,0 +1,23 @@
+// 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 "mojo/environment/default_run_loop_impl.h"
+
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+
+namespace mojo {
+namespace internal {
+
+void InstantiateDefaultRunLoopImpl() {
+  // Not leaked: accessible from |base::MessageLoop::current()|.
+  new base::MessageLoop();
+}
+
+void DestroyDefaultRunLoopImpl() {
+  delete base::MessageLoop::current();
+}
+
+}  // namespace internal
+}  // namespace mojo

mojo/environment/default_run_loop_impl.h

@@ -0,0 +1,19 @@
+// 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.
+
+#ifndef MOJO_ENVIRONMENT_DEFAULT_RUN_LOOP_IMPL_H_
+#define MOJO_ENVIRONMENT_DEFAULT_RUN_LOOP_IMPL_H_
+
+#include "mojo/environment/mojo_environment_impl_export.h"
+
+namespace mojo {
+namespace internal {
+
+MOJO_ENVIRONMENT_IMPL_EXPORT void InstantiateDefaultRunLoopImpl();
+MOJO_ENVIRONMENT_IMPL_EXPORT void DestroyDefaultRunLoopImpl();
+
+}  // namespace internal
+}  // namespace mojo
+
+#endif  // MOJO_ENVIRONMENT_DEFAULT_RUN_LOOP_IMPL_H_

mojo/environment/environment.cc

@@ -6,6 +6,7 @@
 
 #include "mojo/environment/default_async_waiter_impl.h"
 #include "mojo/environment/default_logger_impl.h"
+#include "mojo/environment/default_run_loop_impl.h"
 
 namespace mojo {
 
@@ -33,4 +34,14 @@ const MojoLogger* Environment::GetDefaultLogger() {
   return internal::GetDefaultLoggerImpl();
 }
 
+// static
+void Environment::InstantiateDefaultRunLoop() {
+  internal::InstantiateDefaultRunLoopImpl();
+}
+
+// static
+void Environment::DestroyDefaultRunLoop() {
+  internal::DestroyDefaultRunLoopImpl();
+}
+
 }  // namespace mojo

mojo/mojo_base.gyp

@@ -133,6 +133,8 @@
         'environment/default_async_waiter_impl.h',
         'environment/default_logger_impl.cc',
         'environment/default_logger_impl.h',
+        'environment/default_run_loop_impl.cc',
+        'environment/default_run_loop_impl.h',
       ],
       'include_dirs': [
         '..',