Merge 150896 "Dirty the first RootInlineBox, always"

Source/core/rendering/RenderText.cpp

Index: Source/core/rendering/RenderText.cpp
===================================================================
--- Source/core/rendering/RenderText.cpp	(revision 152061)
+++ Source/core/rendering/RenderText.cpp	(working copy)
@@ -1285,12 +1285,10 @@
             RootInlineBox* root = curr->root();
             if (!firstRootBox) {
                 firstRootBox = root;
-                if (!dirtiedLines) {
-                    // The affected area was in between two runs. Go ahead and mark the root box of
-                    // the run after the affected area as dirty.
-                    firstRootBox->markDirty();
-                    dirtiedLines = true;
-                }
+                // The affected area was in between two runs. Go ahead and mark the root box of
+                // the run after the affected area as dirty.
+                firstRootBox->markDirty();
+                dirtiedLines = true;
             }
             lastRootBox = root;
         } else if (curr->end() >= offset && curr->end() <= end) {