Expose InlineTextBoxes in the accessibility tree.

Source/core/rendering/InlineTextBox.cpp

Index: Source/core/rendering/InlineTextBox.cpp
diff --git a/Source/core/rendering/InlineTextBox.cpp b/Source/core/rendering/InlineTextBox.cpp
index 2e3d986fc8a34b7a0f0a8890f28a5e6fc999cfb5..191dd49f68c94ab6466b9a1603de285919602b31 100644
--- a/Source/core/rendering/InlineTextBox.cpp
+++ b/Source/core/rendering/InlineTextBox.cpp
@@ -35,6 +35,7 @@
 #include "core/platform/graphics/DrawLooper.h"
 #include "core/platform/graphics/FontCache.h"
 #include "core/platform/graphics/GraphicsContextStateSaver.h"
+#include "core/platform/graphics/WidthIterator.h"
 #include "core/rendering/EllipsisBox.h"
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/PaintInfo.h"
@@ -1485,6 +1486,30 @@ bool InlineTextBox::containsCaretOffset(int offset) const
     return true;
 }
 
+void InlineTextBox::characterWidths(Vector<float>& widths) const

[eseidel, 2013/09/10 22:22:23]

This function seems OK to me.  I'm surprised it's needed (that we can't get this
information some other way w/o adding another method to InlineTextBox".  But I'm
OK with this part of the change.

+{
+    FontCachePurgePreventer fontCachePurgePreventer;
+
+    RenderText* textObj = textRenderer();
+    RenderStyle* styleToUse = textObj->style(isFirstLineStyle());
+    const Font& font = styleToUse->font();
+
+    StringBuilder charactersWithHyphen;
+    TextRun textRun = constructTextRun(styleToUse, font, hasHyphen() ? &charactersWithHyphen : 0);
+
+    GlyphBuffer glyphBuffer;
+    WidthIterator it(&font, textRun);
+    float lastWidth = 0;
+    widths.resize(m_len);
+    for (unsigned i = 0; i < m_len; i++) {
+        it.advance(i + 1, &glyphBuffer);
+        widths[i] = it.m_runWidthSoFar - lastWidth;
+        if (textRun.rtl())
+            widths[i] *= -1;
+        lastWidth = it.m_runWidthSoFar;
+    }
+}
+
 TextRun InlineTextBox::constructTextRun(RenderStyle* style, const Font& font, StringBuilder* charactersWithHyphen) const
 {
     ASSERT(style);