Workaround for setComposition styling clobber

third_party/WebKit/Source/core/editing/InputMethodControllerTest.cpp

 // 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 "core/editing/InputMethodController.h"
 
 #include "core/dom/Document.h"
 #include "core/dom/Element.h"
 #include "core/dom/Range.h"
 #include "core/editing/Editor.h"
@@ skipping 97 matching lines @@
     underlines.append(CompositionUnderline(0, 5, Color(255, 0, 0), false, 0));
     controller().setCompositionFromExistingText(underlines, 0, 5);
 
     Range* range = controller().compositionRange();
     EXPECT_EQ(0, range->startOffset());
     EXPECT_EQ(5, range->endOffset());
 
     PlainTextRange plainTextRange(PlainTextRange::create(*div, *range));
     EXPECT_EQ(0u, plainTextRange.start());
     EXPECT_EQ(5u, plainTextRange.end());
+
+    controller().setComposition(String("hellobar"), underlines, 8, 8);
+    range = controller().compositionRange();
+    EXPECT_EQ(0, range->startOffset());
+    EXPECT_EQ(8, range->endOffset());
+}
+
+TEST_F(InputMethodControllerTest, SetCompositionKeepingStyle)
+{
+    // (UTF16) 0xac000 0xb098 0xb2e4 0xb77c = "가나다라"

[aelias_OOO_until_Jul13, 2016/09/27 04:55:58]

Can you also add a simpler test case appending and removing single letters to
English text?

[yabinh, 2016/09/27 08:47:20]

Done.

+    Element* div = insertHTMLElement(
+        "<div id='sample' contenteditable='true'><b>&#xac00&#xb098</b>&#xb2e4&#xb77c</div>", "sample");
+
+    Vector<CompositionUnderline> underlines;
+    underlines.append(CompositionUnderline(0, 4, Color(255, 0, 0), false, 0));
+    controller().setCompositionFromExistingText(underlines, 0, 4);
+
+    // (UTF8) 0xEAB080 0xEB8298 0xEB8BA4 0xEB9E8C = "가나다람"
+    controller().setComposition(String::fromUTF8("\xea\xb0\x80\xeb\x82\x98\xeb\x8b\xa4\xeb\x9e\x8c"), underlines, 4, 4);
+    EXPECT_STREQ("<b>가나</b>다람", div->innerHTML().utf8().data());
+
+    // (UTF8) 0xEAB080 0xEB8298 0xEB8BA4 0xeb9dbc = "가나다라"
+    controller().setComposition(String::fromUTF8("\xea\xb0\x80\xeb\x82\x98\xeb\x8b\xa4\xeb\x9d\xbc"), underlines, 4, 4);
+    EXPECT_STREQ("<b>가나</b>다라", div->innerHTML().utf8().data());
 }
 
 TEST_F(InputMethodControllerTest, SelectionOnConfirmExistingText)
 {
     insertHTMLElement(
         "<div id='sample' contenteditable='true'>hello world</div>", "sample");
 
     Vector<CompositionUnderline> underlines;
     underlines.append(CompositionUnderline(0, 5, Color(255, 0, 0), false, 0));
     controller().setCompositionFromExistingText(underlines, 0, 5);
@@ skipping 350 matching lines @@
     Vector<CompositionUnderline> underlines;
     underlines.append(CompositionUnderline(0, 5, Color(255, 0, 0), false, 0));
     editable->focus();
 
     document().setTitle(emptyString());
     controller().setComposition("n", underlines, 0, 1);
     EXPECT_STREQ("beforeinput.data:n;input.data:n;", document().title().utf8().data());
 
     document().setTitle(emptyString());
     controller().setComposition("ni", underlines, 0, 1);
-    EXPECT_STREQ("beforeinput.data:ni;input.data:ni;", document().title().utf8().data());
+    EXPECT_STREQ("beforeinput.data:i;input.data:i;", document().title().utf8().data());
 
     document().setTitle(emptyString());
     controller().finishComposingText(InputMethodController::KeepSelection);
     EXPECT_STREQ("beforeinput.data:ni;input.data:ni;", document().title().utf8().data());
 }
 
 } // namespace blink