RTHB: Limit text to 10k code units

ui/gfx/render_text_harfbuzz.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/render_text_harfbuzz.h"
 
 #include <limits>
 #include <map>
 
 #include "base/i18n/bidi_line_iterator.h"
@@ skipping 10 matching lines @@
 #include "ui/gfx/utf16_indexing.h"
 
 #if defined(OS_WIN)
 #include "ui/gfx/font_fallback_win.h"
 #endif
 
 namespace gfx {
 
 namespace {
 
+// Text length limit. Longer strings are slow and not fully tested.
+const size_t kMaxTextLength = 10000;
+
 // The maximum number of scripts a Unicode character can belong to. This value
 // is arbitrarily chosen to be a good limit because it is unlikely for a single
 // character to belong to more scripts.
 const size_t kMaxScripts = 5;
 
 // Maps from code points to glyph indices in a font.
 typedef std::map<uint32_t, uint16_t> GlyphCache;
 
 // Font data provider for HarfBuzz using Skia. Copied from Blink.
 // TODO(ckocagil): Eliminate the duplication. http://crbug.com/368375
@@ skipping 524 matching lines @@
   }
 
   return Range(preceding_run_widths_int + cluster_begin_x,
                preceding_run_widths_int + cluster_end_x);
 }
 
 }  // namespace internal
 
 RenderTextHarfBuzz::RenderTextHarfBuzz()
     : RenderText(),
-      needs_layout_(false) {}
+      needs_layout_(false) {
+  set_truncate_length(kMaxTextLength);
+}
 
 RenderTextHarfBuzz::~RenderTextHarfBuzz() {}
 
 Size RenderTextHarfBuzz::GetStringSize() {
   const SizeF size_f = GetStringSizeF();
   return Size(std::ceil(size_f.width()), size_f.height());
 }
 
 SizeF RenderTextHarfBuzz::GetStringSizeF() {
   EnsureLayout();
@@ skipping 595 matching lines @@
       run->width = std::floor(run->width + 0.5f);
 #endif
   }
 
   hb_buffer_destroy(buffer);
   hb_font_destroy(harfbuzz_font);
   return true;
 }
 
 }  // namespace gfx