HTMLConstructionSite: avoid n^2 running time for large scripts.

Source/core/html/parser/HTMLConstructionSite.cpp

Index: Source/core/html/parser/HTMLConstructionSite.cpp
diff --git a/Source/core/html/parser/HTMLConstructionSite.cpp b/Source/core/html/parser/HTMLConstructionSite.cpp
index e917706e404508585197e974f3bc50e4018ffa3e..97d7976ad25b072bf18fdcee005b907ecfe877e4 100644
--- a/Source/core/html/parser/HTMLConstructionSite.cpp
+++ b/Source/core/html/parser/HTMLConstructionSite.cpp
@@ -231,11 +231,14 @@ static String atomizeIfAllWhitespace(const String& string, WhitespaceMode whites
     return string;
 }
 
-void HTMLConstructionSite::flushPendingText()
+void HTMLConstructionSite::flushPendingText(bool force)
 {
     if (m_pendingText.isEmpty())
         return;
 
+    if (!force && !shouldUseLengthLimit(*m_pendingText.parent))
+        return;
+
     PendingText pendingText;
     // Hold onto the current pending text on the stack so that queueTask doesn't recurse infinitely.
     m_pendingText.swap(pendingText);
@@ -269,7 +272,7 @@ void HTMLConstructionSite::flushPendingText()
 
 void HTMLConstructionSite::queueTask(const HTMLConstructionSiteTask& task)
 {
-    flushPendingText();
+    flushPendingText(true);
     ASSERT(m_pendingText.isEmpty());
     m_taskQueue.append(task);
 }
@@ -689,7 +692,7 @@ void HTMLConstructionSite::insertTextNode(const String& string, WhitespaceMode w
     // The nextChild != dummy.nextChild case occurs whenever foster parenting happened and we hit a new text node "<table>a</table>b"
     // In either case we have to flush the pending text into the task queue before making more.
     if (!m_pendingText.isEmpty() && (m_pendingText.parent != dummyTask.parent ||  m_pendingText.nextChild != dummyTask.nextChild))
-        flushPendingText();
+        flushPendingText(true);

[eseidel, 2014/08/23 19:39:59]

We'll need to fix this to be an enum (bools make for unreadable callsites), and
I'll need to think harder about this patch on monday.  But I'm certainly open to
the idea. :)

[eustas, 2014/08/26 08:12:25]

Added enum.

Now codesearch is working again. I've found that some execution paths require
mandatory flush. I've added flush mode to ::flush itself and updated
HTMLTreeBuilder.

     m_pendingText.append(dummyTask.parent, dummyTask.nextChild, string, whitespaceMode);
 }