[ios] Adds unittests for blocks and NSRegularExpression.

ios/chrome/common/block_unittest.mm

+// Copyright (c) 2012 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.
+
+#import <Foundation/Foundation.h>
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "testing/platform_test.h"
+
+// This test verifies assumptions about the murky world of interaction between
+// C++ objects and blocks. Just to make sure.
+
+namespace {
+
+class RefCountedObject : public base::RefCounted<RefCountedObject> {
+ public:
+  RefCountedObject(){};

[sdefresne, 2016/11/07 13:54:57]

Remove trailing semi-colon ...

[rohitrao (ping after 24h), 2016/11/07 14:04:05]

Done.

+
+  // Refcount is private in the superclass, fake it by counting how many times
+  // release can be called until there is one count left, then retain the count
+  // back.
+  int refcount() {
+    int count = 1;
+    while (!HasOneRef()) {
+      bool check = base::subtle::RefCountedBase::Release();
+      EXPECT_FALSE(check);
+      ++count;
+    }
+    for (int ii = 1; ii < count; ii++)

[sdefresne, 2016/11/07 13:54:57]

nit: why "ii" and not "i"?

[rohitrao (ping after 24h), 2016/11/07 14:04:05]

I tend to use "ii" because it doesn't commonly occur in words, making it easier
to grep for.

+      base::subtle::RefCountedBase::AddRef();
+    return count;
+  }
+
+ protected:
+  friend base::RefCounted<RefCountedObject>;
+  virtual ~RefCountedObject(){};

[sdefresne, 2016/11/07 13:54:57]

Remove trailing semi-colon ...

[rohitrao (ping after 24h), 2016/11/07 14:04:05]

Done.

+};
+
+TEST_F(PlatformTest, BlockAndCPlusPlus) {
+  RefCountedObject* object = new RefCountedObject();
+  object->AddRef();
+  EXPECT_TRUE(object->HasOneRef());
+  EXPECT_EQ(1, object->refcount());
+
+  {
+    scoped_refptr<RefCountedObject> object_test_ptr(object);
+    EXPECT_EQ(2, object->refcount());
+  }
+  EXPECT_TRUE(object->HasOneRef());
+
+  void (^heap_block)(int) = 0;
+  {
+    scoped_refptr<RefCountedObject> object_ptr(object);
+    EXPECT_EQ(2, object->refcount());
+    void* object_void_ptr = (void*)object;
+
+    void (^stack_block)(int) = ^(int expected) {
+      EXPECT_EQ(object_void_ptr, object_ptr.get());
+      EXPECT_EQ(expected, object_ptr.get()->refcount());
+    };
+    stack_block(3);
+    heap_block = [stack_block copy];
+    stack_block(4);
+  }
+  heap_block(2);
+  [heap_block release];
+  EXPECT_TRUE(object->HasOneRef());
+  {
+    scoped_refptr<RefCountedObject> object_test2_ptr(object);
+    EXPECT_EQ(2, object->refcount());
+  }
+  EXPECT_TRUE(object->HasOneRef());
+  object->Release();
+}
+
+TEST_F(PlatformTest, BlockAndVectors) {
+  void (^heap_block)(void) = 0;
+  {
+    std::vector<int> vector;
+    vector.push_back(0);
+    vector.push_back(1);
+    vector.push_back(2);
+
+    void (^stack_block)(void) = ^{
+      EXPECT_EQ(3ul, vector.size());
+      EXPECT_EQ(2, vector[2]);
+    };
+    stack_block();
+    vector[2] = 42;
+    vector.push_back(22);
+    stack_block();
+    heap_block = [stack_block copy];
+    stack_block();
+  }
+  heap_block();
+  [heap_block release];
+}
+
+}  // namespace