Undo an incorrect change to selectedRange behavior.

In r661714, I changed -[RenderWidgetHostViewCocoa selectedRange] to
account for the selection offset. But, it turns out that's already
accounted for; I mis-interpreted some other behavior.

This change effectively reverts that one
(7b4466da) but keeps the new test case.

Bug: 42434
Change-Id: I4c738abd5207d447260c98d6293a560f9694d3f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1649143
Auto-Submit: Sidney San Martín <sdy@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#667212}

content/app_shim_remote_cocoa/render_widget_host_view_cocoa.mm

@@ -1571,8 +1571,7 @@ extern NSString* NSTextInputReplacementRangeAttributeName;
 }
 
 - (NSRange)selectedRange {
-  return NSMakeRange(textSelectionRange_.GetMin() + textSelectionOffset_,
-                     textSelectionRange_.length());
+  return textSelectionRange_.ToNSRange();
 }
 
 - (NSRange)markedRange {

content/browser/renderer_host/render_widget_host_view_mac_unittest.mm

@@ -572,7 +572,7 @@ TEST_F(RenderWidgetHostViewMacTest, NSTextInputClientConformance) {
 
   rwhv_mac_->SelectionChanged(base::UTF8ToUTF16("llo, world!"), 2,
                               gfx::Range(5, 10));
-  EXPECT_NSEQ(NSMakeRange(7, 5), [rwhv_cocoa_ selectedRange]);
+  EXPECT_NSEQ(NSMakeRange(5, 5), [rwhv_cocoa_ selectedRange]);
 
   NSRange actualRange = NSMakeRange(1u, 2u);
   NSAttributedString* actualString = [rwhv_cocoa_