linux_aura: Make X11 selection buffers work on text in both direction.

content/browser/renderer_host/render_widget_host_view_aura.cc

Index: content/browser/renderer_host/render_widget_host_view_aura.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_aura.cc b/content/browser/renderer_host/render_widget_host_view_aura.cc
index a590fd7651d3557fdba3279b0a49084723275d96..b6816721a5615b20ade25162d986c87967c0666b 100644
--- a/content/browser/renderer_host/render_widget_host_view_aura.cc
+++ b/content/browser/renderer_host/render_widget_host_view_aura.cc
@@ -37,6 +37,7 @@
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
+#include "ui/base/clipboard/scoped_clipboard_writer.h"
 #include "ui/base/events/event.h"
 #include "ui/base/gestures/gesture_recognizer.h"
 #include "ui/base/hit_test.h"
@@ -525,6 +526,31 @@ void RenderWidgetHostViewAura::SetTooltipText(const string16& tooltip_text) {
     aura::client::GetTooltipClient(root_window)->UpdateTooltip(window_);
 }
 
+void RenderWidgetHostViewAura::SelectionChanged(const string16& text,
+                                                size_t offset,
+                                                const ui::Range& range) {
+  RenderWidgetHostViewBase::SelectionChanged(text, offset, range);
+
+#if defined(USE_X11) && !defined(OS_CHROMEOS)
+  if (text.empty() || range.is_empty())
+    return;
+  size_t pos = range.GetMin() - offset;

[Daniel Erat, 2012/09/14 18:33:15]

is there any danger of negative overflow here?

[Elliot Glaysher, 2012/09/14 20:16:16]

I believe so. This check was added by penghuang@ in the gtk version, so I assume
this is IME fiddliness.

[Daniel Erat, 2012/09/14 20:38:17]

sorry -- i meant, should there also be:

  if (offset > range.GetMin()) {
    NOTREACHED() << "Offset " << offset << " makes range starting at "
                 << range.GetMin() << " precede beginning of text";
    return;
  }

?  pos will be huge in this case, which means we should hit the next
NOTREACHED(), so maybe it's not a big deal.

+  size_t n = range.length();

[Daniel Erat, 2012/09/14 18:33:15]

nit: you'll end up with the same number of lines but more-readable-code, IMHO,
if you remove this and just do:

  DCHECK(pos + range.length() <= text.length())
      << "The text cannot fully cover the range";

+
+  DCHECK(pos + n <= text.length()) << "The text can not fully cover range.";
+  if (pos >= text.length()) {
+    NOTREACHED() << "The text can not cover range.";
+    return;
+  }
+
+  // Set the BUFFER_SELECTION to the ui::Clipboard.
+  ui::ScopedClipboardWriter clipboard_writer(
+      ui::Clipboard::GetForCurrentThread(),
+      ui::Clipboard::BUFFER_SELECTION);
+  clipboard_writer.WriteText(text);
+#endif  // defined(USE_X11) && !defined(OS_CHROMEOS)
+}
+
 void RenderWidgetHostViewAura::SelectionBoundsChanged(
     const gfx::Rect& start_rect,
     WebKit::WebTextDirection start_direction,