Add base::RefCountedString16

Move RefCountedString16 from exo DataOffer to base where it can be
reused.

Change-Id: I0a3e13b006d690be1605c90da6d46274c4811685
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2507235
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Auto-Submit: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#822791}

base/memory/ref_counted_memory.cc

@@ -83,6 +83,26 @@ size_t RefCountedString::size() const {
   return data_.size();
 }
 
+RefCountedString16::RefCountedString16() = default;
+
+RefCountedString16::~RefCountedString16() = default;
+
+// static
+scoped_refptr<RefCountedString16> RefCountedString16::TakeString(
+    string16* to_destroy) {
+  auto self = MakeRefCounted<RefCountedString16>();
+  to_destroy->swap(self->data_);
+  return self;
+}
+
+const unsigned char* RefCountedString16::front() const {
+  return reinterpret_cast<const unsigned char*>(data_.data());
+}
+
+size_t RefCountedString16::size() const {
+  return data_.size() * sizeof(char16);
+}
+
 RefCountedSharedMemoryMapping::RefCountedSharedMemoryMapping(
     ReadOnlySharedMemoryMapping mapping)
     : mapping_(std::move(mapping)), size_(mapping_.size()) {

base/memory/ref_counted_memory.h

@@ -15,6 +15,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory_mapping.h"
+#include "base/strings/string16.h"
 
 namespace base {
 
@@ -144,6 +145,28 @@ class BASE_EXPORT RefCountedString : public RefCountedMemory {
   DISALLOW_COPY_AND_ASSIGN(RefCountedString);
 };
 
+// An implementation of RefCountedMemory, where the bytes are stored in a
+// string16.
+class BASE_EXPORT RefCountedString16 : public base::RefCountedMemory {
+ public:
+  RefCountedString16();
+
+  // Constructs a RefCountedString16 object by performing a swap.
+  static scoped_refptr<RefCountedString16> TakeString(string16* to_destroy);
+
+  // RefCountedMemory:
+  const unsigned char* front() const override;
+  size_t size() const override;
+
+ protected:
+  ~RefCountedString16() override;
+
+ private:
+  string16 data_;
+
+  DISALLOW_COPY_AND_ASSIGN(RefCountedString16);
+};
+
 // An implementation of RefCountedMemory, where the bytes are stored in
 // ReadOnlySharedMemoryMapping.
 class BASE_EXPORT RefCountedSharedMemoryMapping : public RefCountedMemory {

components/exo/data_offer.cc

@@ -44,28 +44,6 @@ constexpr char kUriListSeparator[] = "\r\n";
 constexpr char kUTF8[] = "utf8";
 constexpr char kUTF16[] = "utf16";
 
-class RefCountedString16 : public base::RefCountedMemory {
- public:
-  static scoped_refptr<RefCountedString16> TakeString(
-      base::string16&& to_destroy) {
-    scoped_refptr<RefCountedString16> self(new RefCountedString16);
-    to_destroy.swap(self->data_);
-    return self;
-  }
-
-  // Overridden from base::RefCountedMemory:
-  const unsigned char* front() const override {
-    return reinterpret_cast<const unsigned char*>(data_.data());
-  }
-  size_t size() const override { return data_.size() * sizeof(base::char16); }
-
- protected:
-  ~RefCountedString16() override {}
-
- private:
-  base::string16 data_;
-};
-
 void WriteFileDescriptorOnWorkerThread(
     base::ScopedFD fd,
     scoped_refptr<base::RefCountedMemory> memory) {
@@ -259,7 +237,7 @@ void DataOffer::SetDropData(FileHelper* file_helper,
   base::string16 url_list_string;
   if (GetUrlListFromDataFile(file_helper, data, &url_list_string)) {
     data_.emplace(uri_list_mime_type,
-                  RefCountedString16::TakeString(std::move(url_list_string)));
+                  base::RefCountedString16::TakeString(&url_list_string));
     delegate_->OnOffer(uri_list_mime_type);
     return;
   }
@@ -374,7 +352,7 @@ void DataOffer::OnPickledUrlsResolved(const std::string& mime_type,
     url_list_string += base::UTF8ToUTF16(url.spec());
   }
   const auto ref_counted_memory =
-      RefCountedString16::TakeString(std::move(url_list_string));
+      base::RefCountedString16::TakeString(&url_list_string);
   data_.emplace(mime_type, ref_counted_memory);
 
   // Process pending receive requests for this mime type, if there are any.