Avoid setting ImeTextSpan::underline_color on Windows

Like the rest of the platforms, this patch avoids
setting ImeTextSpan::underline_color to black color.
That way when the IME composition underline is painted it'll use
the text color and not be always black.

This makes the composition underline visible when you have
a dark background.

Bug: 1168012
Change-Id: Id4ec27ffe8e698ff41de93fc1260363f96e4aa3b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2637495Reviewed-by: Yohei Yukawa <yukawa@chromium.org>
Commit-Queue: Manuel Rego <rego@igalia.com>
Cr-Commit-Position: refs/heads/master@{#845548}

ui/base/ime/win/imm32_manager.cc

@@ -77,7 +77,6 @@ void GetImeTextSpans(HIMC imm_context,
         ui::ImeTextSpan ime_text_span;
         ime_text_span.start_offset = clause_data[i];
         ime_text_span.end_offset = clause_data[i + 1];
-        ime_text_span.underline_color = SK_ColorBLACK;
         ime_text_span.thickness = ui::ImeTextSpan::Thickness::kThin;
         ime_text_span.background_color = SK_ColorTRANSPARENT;
 

ui/base/ime/win/tsf_text_store.cc

@@ -1081,7 +1081,6 @@ bool TSFTextStore::GetCompositionStatus(
       ImeTextSpan span;
       span.start_offset = start_pos;
       span.end_offset = start_pos + length;
-      span.underline_color = SK_ColorBLACK;
       span.background_color = SK_ColorTRANSPARENT;
       if (selection_.EqualsIgnoringDirection(
               gfx::Range(span.start_offset, span.end_offset))) {