Do another merge using nifty new merge script (CL for that coming soon).

third_party/WebKit/WebCore/editing/DeleteSelectionCommand.cpp

Index: third_party/WebKit/WebCore/editing/DeleteSelectionCommand.cpp
===================================================================
--- third_party/WebKit/WebCore/editing/DeleteSelectionCommand.cpp	(revision 5296)
+++ third_party/WebKit/WebCore/editing/DeleteSelectionCommand.cpp	(working copy)
@@ -79,6 +79,7 @@
       m_mergeBlocksAfterDelete(mergeBlocksAfterDelete),
       m_replace(replace),
       m_expandForSpecialElements(expandForSpecialElements),
+      m_pruneStartBlockIfNecessary(false),
       m_startBlock(0),
       m_endBlock(0),
       m_typingStyle(0),
@@ -93,6 +94,7 @@
       m_mergeBlocksAfterDelete(mergeBlocksAfterDelete),
       m_replace(replace),
       m_expandForSpecialElements(expandForSpecialElements),
+      m_pruneStartBlockIfNecessary(false),
       m_selectionToDelete(selection),
       m_startBlock(0),
       m_endBlock(0),
@@ -189,6 +191,15 @@
         m_endingPosition = m_downstreamEnd;
     else
         m_endingPosition = m_downstreamStart;
+    
+    // We don't want to merge into a block if it will mean changing the quote level of content after deleting 
+    // selections that contain a whole number paragraphs plus a line break, since it is unclear to most users 
+    // that such a selection actually ends at the start of the next paragraph. This matches TextEdit behavior 
+    // for indented paragraphs.
+    if (numEnclosingMailBlockquotes(start) != numEnclosingMailBlockquotes(end) && isStartOfParagraph(visibleEnd) && isStartOfParagraph(VisiblePosition(start))) {
+        m_mergeBlocksAfterDelete = false;
+        m_pruneStartBlockIfNecessary = true;
+    }
 
     // Handle leading and trailing whitespace, as well as smart delete adjustments to the selection
     m_leadingWhitespace = m_upstreamStart.leadingWhitespacePosition(m_selectionToDelete.affinity());
@@ -510,8 +521,21 @@
 // start together with content after the end.
 void DeleteSelectionCommand::mergeParagraphs()
 {
-    if (!m_mergeBlocksAfterDelete)
+    if (!m_mergeBlocksAfterDelete) {
+        if (m_pruneStartBlockIfNecessary) {
+            // Make sure that the ending position isn't inside the block we're about to prune.
+            m_endingPosition = m_downstreamEnd;
+            // We aren't going to merge into the start block, so remove it if it's empty.
+            prune(m_upstreamStart.node());
+            // Removing the start block during a deletion is usually an indication that we need
+            // a placeholder, but not in this case.
+            m_needPlaceholder = false;
+        }
         return;
+    }
+    
+    // It shouldn't have been asked to both try and merge content into the start block and prune it.
+    ASSERT(!m_pruneStartBlockIfNecessary);
 
     // FIXME: Deletion should adjust selection endpoints as it removes nodes so that we never get into this state (4099839).
     if (!m_downstreamEnd.node()->inDocument() || !m_upstreamStart.node()->inDocument())