Introduce Range::dispose() for prompt detachment from owner Document.

Source/web/WebLocalFrameImpl.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 237 matching lines @@
 static void frameContentAsPlainText(size_t maxChars, LocalFrame* frame, StringBuilder& output)
 {
     Document* document = frame->document();
     if (!document)
         return;
 
     if (!frame->view())
         return;
 
     // Select the document body.
     RefPtrWillBeRawPtr<Range> range(document->createRange());

[yosin_UTC9, 2015/09/11 07:07:19]

Thus, we don't need to use |Range|.
We may want to move this change in another CL.

[sof, 2015/09/11 07:11:42]

I'm sorry, spaced out completely - we clearly don't need this Range allocation.
Now g/done.

-    TrackExceptionState exceptionState;
-    range->selectNodeContents(document->body(), exceptionState);
+    ScopedDisposal<Range> disposeScope(range.get());
 
-    if (!exceptionState.hadException()) {
+    if (document->body()) {
+        const EphemeralRange range = EphemeralRange::rangeOfContents(*document->body());
+
         // The text iterator will walk nodes giving us text. This is similar to
         // the plainText() function in core/editing/TextIterator.h, but we implement the maximum
         // size and also copy the results directly into a wstring, avoiding the
         // string conversion.
-        for (TextIterator it(range->startPosition(), range->endPosition()); !it.atEnd(); it.advance()) {
+        for (TextIterator it(range.startPosition(), range.endPosition()); !it.atEnd(); it.advance()) {
             it.text().appendTextToStringBuilder(output, 0, maxChars - output.length());
             if (output.length() >= maxChars)
                 return; // Filled up the buffer.
         }
     }
 
     // The separator between frames when the frames are converted to plain text.
     const LChar frameSeparator[] = { '\n', '\n' };
     const size_t frameSeparatorLength = WTF_ARRAY_LENGTH(frameSeparator);
 
@@ skipping 1915 matching lines @@
 }
 
 WebSandboxFlags WebLocalFrameImpl::effectiveSandboxFlags() const
 {
     if (!frame())
         return WebSandboxFlags::None;
     return static_cast<WebSandboxFlags>(frame()->loader().effectiveSandboxFlags());
 }
 
 } // namespace blink