Use the font height as caret height instead of the line height

third_party/WebKit/Source/core/layout/LayoutText.cpp

Index: third_party/WebKit/Source/core/layout/LayoutText.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutText.cpp b/third_party/WebKit/Source/core/layout/LayoutText.cpp
index d6cc72e451eedaad34ef2b71ad43a2af188884a5..6962450da978db8658d114766e75a6a28b1fa98a 100644
--- a/third_party/WebKit/Source/core/layout/LayoutText.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutText.cpp
@@ -732,9 +732,16 @@ LayoutRect LayoutText::localCaretRect(InlineBox* inlineBox,
     return LayoutRect();
 
   InlineTextBox* box = toInlineTextBox(inlineBox);
-
-  int height = box->root().selectionHeight().toInt();
-  int top = box->root().selectionTop().toInt();
+  // Find an InlineBox before caret position, which is used to get caret height.
+  InlineBox* caretBox = box;
+  if (box->prevLeafChild() && caretOffset == 0)

[drott, 2016/12/14 16:42:22]

In https://bugs.chromium.org/p/chromium/issues/detail?id=588060#c12 Yosin
mentions 
"The actual font for calculating caret rectangle should be taken from a
character around caret in following order:
1. a character before caret; left for dir=LTR, right for dir=RTL"

So, I believe this needs to take RTL into account here, and it would be good to
have an additional test which covers and illustrates this font boundary size
change. 

+    caretBox = box->prevLeafChild();
+
+  // Get caret height from a font of character.
+  const ComputedStyle* styleToUse =
+      caretBox->getLineLayoutItem().style(caretBox->isFirstLineStyle());
+  int height = styleToUse->font().primaryFont()->getFontMetrics().height();
+  int top = caretBox->logicalTop().toInt();
 
   // Go ahead and round left to snap it to the nearest pixel.
   LayoutUnit left = box->positionForOffset(caretOffset);