fxcrt::{Byte,Wide}String missing move-assign operator

This hasn't been a big deal, since no data is copied, but avoids
some ref-count churn in the process.

Change-Id: I53c059284aa6806793c59a0c19b3e0d7fe4191d6
Reviewed-on: https://pdfium-review.googlesource.com/35350
Commit-Queue: dsinclair <dsinclair@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/core/fxcrt/bytestring_unittest.cpp b/core/fxcrt/bytestring_unittest.cpp
index ed3f375434..2b7d4f7836 100644
--- a/core/fxcrt/bytestring_unittest.cpp
+++ b/core/fxcrt/bytestring_unittest.cpp
@@ -59,6 +59,37 @@ TEST(ByteString, ElementAccess) {
 #endif
 }
 
+TEST(ByteString, Assign) {
+  {
+    // Copy-assign.
+    ByteString string1;
+    EXPECT_EQ(0, string1.ReferenceCountForTesting());
+    {
+      ByteString string2("abc");
+      EXPECT_EQ(1, string2.ReferenceCountForTesting());
+
+      string1 = string2;
+      EXPECT_EQ(2, string1.ReferenceCountForTesting());
+      EXPECT_EQ(2, string2.ReferenceCountForTesting());
+    }
+    EXPECT_EQ(1, string1.ReferenceCountForTesting());
+  }
+  {
+    // Move-assign.
+    ByteString string1;
+    EXPECT_EQ(0, string1.ReferenceCountForTesting());
+    {
+      ByteString string2("abc");
+      EXPECT_EQ(1, string2.ReferenceCountForTesting());
+
+      string1 = std::move(string2);
+      EXPECT_EQ(1, string1.ReferenceCountForTesting());
+      EXPECT_EQ(0, string2.ReferenceCountForTesting());
+    }
+    EXPECT_EQ(1, string1.ReferenceCountForTesting());
+  }
+}
+
 TEST(ByteString, OperatorLT) {
   ByteString empty;
   ByteString a("a");