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 5e6648ff1a7b37e4c277973f2be1ba9ff0381128..3eaf7191c84abdd5289a7a420ccb1211ef857e25 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"
@@ -1487,6 +1488,29 @@ bool InlineTextBox::containsCaretOffset(int offset) const
     return true;
 }
 
+void InlineTextBox::characterWidths(float widths[]) const
+{
+    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;
+    for (unsigned i = 0; i < m_len; i++) {
+        it.advance(i + 1, &glyphBuffer);
+        widths[i] = it.m_runWidthSoFar - lastWidth;
+        if (textRun.rtl())
+            widths[i] = -widths[i];
+        lastWidth = it.m_runWidthSoFar;
+    }
+}
+
 TextRun InlineTextBox::constructTextRun(RenderStyle* style, const Font& font, StringBuilder* charactersWithHyphen) const
 {
     ASSERT(style);