[blink/mac] Support getting baseline point for showing dictionary lookup bubble.

Source/web/mac/WebSubstringUtil.mm

Index: Source/web/mac/WebSubstringUtil.mm
diff --git a/Source/web/mac/WebSubstringUtil.mm b/Source/web/mac/WebSubstringUtil.mm
index c5ea739b1a65dad42e4a08db7f25964d5d8decd3..ba20e3e1de82e5be1b20526b5dacc246c3b18a53 100644
--- a/Source/web/mac/WebSubstringUtil.mm
+++ b/Source/web/mac/WebSubstringUtil.mm
@@ -110,6 +110,24 @@ static NSAttributedString* attributedSubstringFromRange(const EphemeralRange& ra
     return [string autorelease];
 }
 
+WebPoint getBaselinePoint(FrameView* frameView, const EphemeralRange& range, const NSAttributedString* string)
+{
+    // Compute bottom left corner and convert to AppKit coordinates.
+    // TODO(yosin) We shold avoid to create |Range| object.

[eae, 2015/09/09 16:56:04]

Could you please file a bug about this and add a link here?

[Shu Chen, 2015/09/10 01:14:07]

Done.

+    IntRect stringRect = enclosingIntRect(createRange(range)->boundingRect());
+    IntPoint stringPoint = stringRect.minXMaxYCorner();
+    stringPoint.setY(frameView->height() - stringPoint.y());

[eae, 2015/09/09 16:56:04]

You take the bottom left corner of the bounding rect for the range and then
adjust it by the height of the frame view. What type of coordinate does that
give you? I know this code was just moved but an explanation here would help.

[Shu Chen, 2015/09/10 01:14:07]

Actually, I don't understand why adjust y() by the height of the frame view.
The y() will be adjusted back when using it at here:
https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/re....

The point type is changed as IntPoint -> WebPoint -> gfx::Point -> CGPoint ->
NSPoint.
I suspect the computation on certain point type requires that strange adjust.

Do you have any ideas?

+
+    // Adjust for the font's descender. AppKit wants the baseline point.
+    if ([string length]) {
+        NSDictionary* attributes = [string attributesAtIndex:0 effectiveRange:NULL];
+        NSFont* font = [attributes objectForKey:NSFontAttributeName];
+        if (font)
+            stringPoint.move(0, ceil(-[font descender]));
+    }
+    return stringPoint;
+}
+
 namespace blink {
 
 NSAttributedString* WebSubstringUtil::attributedWordAtPoint(WebView* view, WebPoint point, WebPoint& baselinePoint)
@@ -118,8 +136,6 @@ NSAttributedString* WebSubstringUtil::attributedWordAtPoint(WebView* view, WebPo
     if (!result.innerNode())
       return nil;
     LocalFrame* frame = result.innerNode()->document().frame();
-    FrameView* frameView = frame->view();
-
     EphemeralRange range = frame->rangeForPoint(result.roundedPointInInnerNodeFrame());
     if (range.isNull())
         return nil;
@@ -131,27 +147,17 @@ NSAttributedString* WebSubstringUtil::attributedWordAtPoint(WebView* view, WebPo
 
     // Convert to NSAttributedString.
     NSAttributedString* string = attributedSubstringFromRange(wordRange);
-
-    // Compute bottom left corner and convert to AppKit coordinates.
-    // TODO(yosin) We shold avoid to create |Range| object.
-    IntRect stringRect = enclosingIntRect(createRange(wordRange)->boundingRect());
-    IntPoint stringPoint = stringRect.minXMaxYCorner();
-    stringPoint.setY(frameView->height() - stringPoint.y());
-
-    // Adjust for the font's descender. AppKit wants the baseline point.
-    if ([string length]) {
-        NSDictionary* attributes = [string attributesAtIndex:0 effectiveRange:NULL];
-        NSFont* font = [attributes objectForKey:NSFontAttributeName];
-        if (font)
-            stringPoint.move(0, ceil(-[font descender]));
-    }
-
-    baselinePoint = stringPoint;
+    baselinePoint = getBaselinePoint(frame->view(), wordRange, string);
     return string;
 }
 
 NSAttributedString* WebSubstringUtil::attributedSubstringInRange(WebLocalFrame* webFrame, size_t location, size_t length)
 {
+    return WebSubstringUtil::attributedSubstringInRange(webFrame, location, length, nil);
+}
+
+NSAttributedString* WebSubstringUtil::attributedSubstringInRange(WebLocalFrame* webFrame, size_t location, size_t length, WebPoint* baselinePoint)
+{
     LocalFrame* frame = toWebLocalFrameImpl(webFrame)->frame();
     if (frame->view()->needsLayout())
         frame->view()->layout();
@@ -163,7 +169,10 @@ NSAttributedString* WebSubstringUtil::attributedSubstringInRange(WebLocalFrame*
     if (ephemeralRange.isNull())
         return nil;
 
-    return attributedSubstringFromRange(ephemeralRange);
+    NSAttributedString* ret = attributedSubstringFromRange(ephemeralRange);
+    if (baselinePoint)
+        *baselinePoint = getBaselinePoint(frame->view(), ephemeralRange, ret);
+    return ret;
 }
 
 } // namespace blink